GM Service Manual Online
For 1990-2009 cars only

Engine Control Module Scan Tool Information L95, LV8, LXT

Table 1: Engine Control Module Scan Tool Data
Table 2: Engine Control Module (ECM) Scan Tool Output Controls

The Engine Control Module Scan Tool Data List contains all engine-related parameters that are available on the scan tool. This is a master list arranged in alphabetical order and not all the parameters listed are in every engine platform.

Use the Engine Scan Tool Data List only after the following is determined:

    • The Diagnostic System Check - Vehicle is completed.
    • No diagnostic trouble codes (DTCs)
    • On-board diagnostics are functioning properly

The scan tool values from a properly running engine may be used for comparison with the engine you are diagnosing. The Engine Scan Tool Data List represents values that would be seen on a normally running engine.

Note: A scan tool that displays faulty data should not be used. The scan tool concern should be reported to the manufacturer. Use of a faulty scan tool can result in misdiagnosis and unnecessary parts replacement.

Only the parameters listed below are referenced in this service manual for use in diagnosis.

Engine Control Module Scan Tool Data

Parameter

System State

Expected Value

Description

Base Operating Conditions: Engine Idling/Radiator Hose Hot/Park or Neutral/Closed Loop

5 Volt Reference 1 or 2

Ignition ON

5 Volts

This parameter displays the output voltage from the 5-volt reference circuit to the control module. This parameter only supports one 5-volt reference output from the control module.

A/C High Side Pressure

A/C OFF

0-5 Volts

This parameter displays the voltage from the A/C high side pressure sensor signal circuit to the control module.

A/C ON

0-5 Volts

A/C High Side Pressure

A/C OFF

450-650 kPa (65-95 psi)

This parameter displays the pressure from the A/C high side pressure sensor signal circuit to the control module.

A/C ON

650-800 kPa (95-105 psi)

A/C Relay Command

A/C ON

On

This parameter displays the state of the air conditioning (A/C) clutch relay control circuit as commanded by the control module.

A/C Request Signal

A/C ON

Yes

This parameter displays the state of the A/C request input to the control module from the heating, ventilation, and air conditioning (HVAC) controls.

Air Flow Calculated

--

3-6 g/s

This parameter displays the calculated air flow into the engine that is based on manifold absolute pressure. The calculation is used in several diagnostics to determine when to run the diagnostics.

Air Fuel Ratio

--

Ratio 14.7:1

This parameter displays the air to fuel ratio based on the oxygen sensor inputs. The engine control module (ECM) uses the fuel trims to adjust fueling in order to attempt to maintain an air fuel ratio of 14.7:1.

APP Indicated Angle

--

Varies

This parameter displays the angle of the accelerator pedal position (APP) as calculated by the control module using the signals from the APP sensors.

APP Sensor 1 or 2

--

Varies

This parameter displays the actual percentage of each APP sensor signal circuit as measured by the control module.

BARO

--

65-104 kPa (8-16 psi) - Varies with altitude

This parameter displays the barometric pressure. The control module uses the barometric pressure sensor input for fuel control to compensate for altitude differences.

Case Diagnostic Learning

--

Learned

This parameter displays Learned if the control module has completed the CKP System Variation Learn Procedure.

Catalytic Converter Protection Active

--

No

This parameter displays if the control module is commanding catalytic converter protection.

Cmmd. A/F Equivalence Ratio

--

Ratio 1.0:1

This parameter displays the air to fuel ratio based on throttle state. The control module changes the ratio for acceleration or deceleration.

CMP Active Counter

--

1-3 Counts

This parameter displays the camshaft position (CMP) active counts. If the control module does not detect a signal from the CMP sensor, the counter will not increment.

Coolant Hot Lamp

--

Off

This parameter displays the control modules commanded state of the hot mode lamp.

Cruise Control Active

Cruise Control ON

Yes

This parameter displays the status of the cruise control system as determined by the control module.

Cruise Disengage 1-5 History

--

Varies

This parameter displays the history of the action taking with the cruise system.

Cruise Lamp Command

Cruise Control ON

Yes

This parameter displays the state of the cruise lamp to the instrument panel (IP) cluster as requested by the control module.

Cruise ON/OFF Switch

Cruise Control ON

Yes

This parameter displays the state of the ON/OFF switch input to the control module.

Cruise Resume/Accel. Switch

Cruise Resume/Accel. Switch ON

Active

This parameter displays the state of the Resume/Accel switch input to the control module from the cruise control system.

Cruise Set/Coast Switch

Cruise Set/Coast Switch ON

Active

This parameter displays the state of the Set/Coast switch input to the control module from the cruise control system.

Decel Fuel Cut Off

--

Inactive

This parameter displays the status of the operating mode of the control module used to turn off the fuel injectors during certain deceleration conditions.

Desired EGR Position

--

Varies

This parameter displays the desired exhaust gas recirculation (EGR) position as commanded by the control module.

Desired IAC Position

--

Counts

This parameter displays the desired idle air control (IAC) position as commanded by the control module.

Desired Idle Speed

--

750-950 RPM

This parameter displays the desired engine idle speed as commanded by the control module.

Distance Since DTC Cleared

--

Varies

This parameter displays the mileage that has elapsed since the DTC cleared.

ECT Sensor

--

-39 to +140°C ( -38 to +284°F)

This parameter displays the temperature of the engine coolant based on input to the control module from the engine coolant temperature (ECT) sensor.

EGR Flow Test Count

--

Counts

This parameter displays the number of EGR flow test samples collected during the current ignition cycle.

EGR Learned Minimum Position

--

Varies

This parameter displays the exhaust gas recirculation (EGR) valve minimum position in percent of range learned by the control module.

EGR Learned Minimum

--

Varies

This parameter displays the learned minimum value of the EGR valve as recorded by the control module during the last learn procedure.

EGR Position Sensor

--

Varies

This parameter displays the actual EGR pintle position in percentage.

EGR Position Sensor

--

Varies

This parameter displays the actual EGR pintle position in volts.

EGR Position Variance

--

Counts

This parameter displays the difference between the actual command of the EGR valve and the desired position of the EGR valve.

EGR Solenoid Command

--

Varies

This parameter displays the state of the control circuit for EGR solenoid as commanded by the control module.

Engine Load

Engine Idling

25-40%

This parameter displays the calculated engine load in percent based on inputs to the control module from various engine sensors.

Engine speed at 2,500 RPM

25-40%

Engine Run Time

Engine Operating

0:00:00

Increments when the engine is operating

This parameter displays the time elapsed since the engine was started.

Engine Speed

Engine Cranking

Greater than 60 RPM

This parameter displays the speed of the engine crankshaft rotation from information received from the crankshaft position (CKP) sensor. If there is a CKP sensor DTC, the ECM calculates the engine speed from one of the camshaft position (CMP) sensors.

Engine Idling

Approximately 750-950 RPM

EVAP Purge Solenoid Command

--

0-100%

This parameter displays the on-time or duty cycle of the EVAP canister purge solenoid commanded by the control module. Zero percent indicates no purge. One hundred percent indicates full purge.

EVAP Vent Solenoid Command

--

Venting

This parameter displays the state of the EVAP vent solenoid as commanded by the control module.

Fail Counter

--

Counts

This parameter displays the number of times a DTC failed

Fan High Speed Command

Fan High Speed ON

On

This parameter displays the control module commanded state of the fan relay control circuit.

Fan Low Speed Command

Fan Low Speed ON

On

This parameter displays the control module commanded state of the fan relay control circuit.

Fuel Level Gage Command

--

Varies

This parameter displays the control module commanded state of the fuel gage control circuit.

Fuel Level to Cluster

--

Varies

This parameter displays the control module commanded state of the fuel gage control circuit.

Fuel Level Sensor

--

0-100%

This parameter displays the amount of fuel in the fuel tank in percent of range, as calculated by the control module.

Fuel Level Sensor

--

0-5 Volts

This parameter displays the voltage signal received by the control module from the fuel level sensor.

Fuel Pump Relay Command

Ignition ON, engine OFF

Fuel pump on for 2 seconds

This parameter displays the control modules commanded state of the fuel pump relay control circuit.

Engine idling

On

Fuel Tank Pressure Sensor

--

Varies

This parameter displays the pressure/vacuum inside the fuel tank. A negative value indicates a vacuum, while a positive value indicates a pressure.

Fuel Tank Pressure Sensor

--

0-5 Volts

This parameter displays the voltage signal received by the control module from the fuel tank pressure (FTP) sensor.

Fuel Trim Cell

--

Cell Number

This parameter displays what fuel trim cell that is currently active.

Fuel Trim Learned

--

Enabled

This parameter displays Enabled when conditions are appropriate for enabling long term fuel trim corrections. This indicates that the long term fuel trim is adapting continuing amounts of short term fuel trim. If the scan tool displays Disabled, then long term fuel trim will not respond to changes in short term fuel trim.

HO2S 1 or HO2S 2 Heater

--

Varies

This parameter displays the amperage of the HO2S heater commanded by the control module.

IAC Position

--

15-40 counts

This parameter displays the engine control module (ECM) command for the IAC pintle position in counts. The higher the number of counts, the greater the commanded idle speed reads. The IAC responds to changes in the engine load in order to maintain the desired idle speed.

IAT Sensor

--

-39° to +140°C

(-38° to +284°F)

This parameter displays the temperature of the air entering the air induction system based on input to the control module from the intake air temperature (IAT) sensor.

Ignition 1 Signal

--

B+

This parameter displays B+ when the control module detects a voltage at the ignition 1 input terminal.

IMT Valve Command

--

Off

This parameter displays the commanded state of the IMT valve solenoid by the control module.

IMT Valve Position Sensor

--

Varies

This parameter displays the percentage in range based on input to the control module the control module from the IMT valve position sensor.

Injector PWM Average

--

0-9 ms

This parameter displays the average pulse width of the fuel injectors as determined by the control module.

Knock Retard

--

Degrees

This parameter indicates the amount of spark advance the control module removes from the ignition control (IC) spark advance in response to the signal from the knock sensors.

KS Active Counter

--

Counts

This parameters displays the number of times the control module detects activity from the knock sensor.

Long Term FT

--

0-2%

This parameter displays the commanded Long Term Fuel Trim correction by the control module.

Long Term FT Average

--

0%

This parameter displays the commanded Long Term Fuel Trim correction by the control module.

Loop Status

--

Closed Loop

This parameter displays the state of the fuel control system as commanded by the control module. Closed Loop operation indicates that the control module is controlling the fuel delivery based off the oxygen sensors input signal. In Open Loop operation the control module ignores the oxygen sensor input signal and bases the amount of fuel to be delivered on other sensor inputs.

Low Fuel Lamp Command

Low Fuel Lamp Command ON

On

This parameter displays the control modules commanded state of the low fuel lamp.

MAP Sensor

--

32-50 kPa

This parameter displays the pressure from the MAP sensor to the control module

MAP Sensor

--

0-5 Volts

This parameter displays the signal voltage from the MAP sensor to the control module.

MIL Command

MIL Command ON

On

This parameter displays the commanded state of the malfunction indicator lamp (MIL) control circuit by the control module.

Mileage Since First Failure

--

Varies

This parameter displays the mileage that has elapsed since the first emission failure.

Mileage Since Last Failure

--

Varies

This parameter displays the mileage that has elapsed since the last emission failure.

Misfire Current Cyl. 1-4

--

0-255 Counts

This parameter displays the number of misfires that have been detected during the last 200 cylinder firing events. The counters may normally display some activity, but the activity should be nearly equal for all of the cylinders, and in low numbers.

Misfire Detects Rough Road

Rough Road Detected

Yes

This parameter displays the detection of a rough road during misfire detection by the control module.

Misfire History Cyl. 1-4

--

0-255 Counts

The misfire history counters display the total level of misfire that has been detected on each cylinder. The misfire history counters will not update or show any activity until a misfire DTC P0300 has become active. The misfire history counters will update every 200 cylinder firing events.

Not Run Counter

--

Counts

This parameter displays the number of times a DTC does not run.

O2S/HO2S 1 or 2

--

Varies 400-800 mV

This parameter displays the voltage output from the H/O2S to the control module. A lower voltage indicates a lean exhaust, while a higher voltage indicates a rich exhaust.

O2S/HO2S 1 Ready

--

Yes

This parameter displays that the HO2S 1 is at operating temperature.

Pass Counter

--

Counts

This parameter displays the number of times a DTC passed.

PNP Switch

--

Park/Neutral

This parameter displays whether the transmission range selector is in park/neutral or in gear.

Power Enrichment

--

Inactive

This parameter displays the status of the operating mode of the control module used to increase fuel delivery during certain acceleration conditions.

Power Steering Pressure Switch

--

Normal Pressure

This parameter displays the state of the power steering pressure switch.

Rich/Lean to Lean/Rich Ratio Sensor 1

--

Counts

This parameter displays the oxygen sensor rich/lean to lean/rich ratio. The rich/lean average is divided by the lean/rich average in order to determine the oxygen sensor ratio.

Rich/Lean to Transition Sensor 1

--

Counts

This parameter displays the oxygen sensor rich/lean and lean/rich switches. A switch is when the oxygen sensor voltage goes above 450 mV and below 450 mV.

Reduced Engine Power

--

No

This parameter displays the status of the operating mode of the control module used to reduce engine power to prevent catalytic converter or engine damage or due to a Throttle Actuator Control (TAC) system failure.

Rough Road Sensor

--

0-5 Volts

This parameter displays the voltage from the rough road sensor.

Rough Road Signal-ABS

--

0-5 Volts

This parameter displays the voltage from the ABS module for the rough road signal.

Short Term FT Avg.

--

-3% to +3%

This parameter displays the short-term correction to the fuel delivery by the control module in response to oxygen sensor. If the oxygen sensor indicates a lean air/fuel mixture, the control module will add fuel increasing the short term fuel trim above 0. If the oxygen sensor indicates a rich air/fuel mixture, the control module will reduce fuel decreasing the short term fuel trim below 0.

Short Term FT

--

-3% to +3%

This parameter displays the short-term correction to the fuel delivery by the control module in response to oxygen sensor. If the oxygen sensor indicates a lean air/fuel mixture, the control module will add fuel increasing the short term fuel trim above 0. If the oxygen sensor indicates a rich air/fuel mixture, the control module will reduce fuel decreasing the short term fuel trim below 0.

Spark

--

-20 to +40Degrees

This parameter displays the amount of spark advance the control module is commanding on the ignition control circuits. The control module determines the desired advance.

Start Up ECT

--

-39° to +140°C

(-38° to +284°F)

This parameter displays the temperature of the engine coolant on start up based on input to the control module from the ECT sensor.

Start Up IAT

--

-39° to +140°C

(-38° to +284°F)

This parameter displays the temperature of the intake air at start in the air induction system based on input to the control module from the IAT sensor.

SVS Lamp Command

SVS Lamp Command ON

On

This parameter displays the control modules commanded state of the service vehicle soon lamp.

TAC Motor Command

TAC Motor Command ON

Varies

This parameter displays the percentage of the commanded state of the TAC motor by the control module.

TCC Enable Solenoid Command

TCC Enable Solenoid Command ON

On

This parameter displays the control module commanded state of the TCC solenoid.

Throttle Plate at Idle

--

Yes

This parameter displays whether the throttle plate at idle or not as calculated by the control module using information from the throttle position (TP) sensor. The scan tool will display Yes for the throttle plate to be at idle. The scan tool will display No when the throttle plate is opened.

Total Misfire

--

Counts

This parameter displays the total number of cylinder firing events that the control module detected as misfires for the last 200 crankshaft revolution sample period.

TP Angle

--

Varies

This parameter displays the percent of throttle opening as calculated by the control module using information from the two TP sensors.

TP Desired Angle

--

Varies

This parameter displays the desired TP angle commanded by the control module.

TP Indicated Angle

--

Varies

This parameter displays the actual TP angle indicated by the control module using information from the two TP sensors.

TP Sensor

--

0.0-0.3 Volts

This parameter displays the actual voltage on the TP sensor signal circuit as measured by the control module.

TP Sensor

--

5-15%

This parameter displays the percent of throttle opening as calculated by the control module using information from the throttle position (TP) sensor.

TP Sensor 1 or 2

--

Varies

This parameter displays the percent of throttle opening as calculated by the control module using information from the throttle position (TP) sensor.

Transmission Gear Position Signal

--

Park/Neutral

This parameter displays the position of the transmission gear selector that is transmitted over the serial data circuit from the transmission control module (TCM).

TWC Temperature Calculated

--

Varies

This parameter displays the catalytic converter temperature as calculated by the control module.

Vehicle Security Status

--

Disabled

This parameter displays the status of the vehicle theft deterrent system. The normal parameter display for the theft deterrent system is Disabled. If a condition exists with the theft deterrent system the parameter will display Enabled and the vehicle will not start.

Vehicle Speed Sensor

--

0 Km/h

0 mph

This parameter displays the speed of the vehicle as calculated by the transmission control module (TCM) from information received from the vehicle speed sensor (VSS).

Warm-ups Since DTC Cleared

--

Counts

This parameter displays the number of warm-ups since the DTC was cleared.

Wheel/Vehicle Speed Input

--

0 Km/h

0 mph

This parameter displays the speed of the vehicle as calculated by the control module from information received from the vehicle speed sensor (VSS) or wheel speed sensor depending on application.

Engine Control Module (ECM) Scan Tool Output Controls

Output Control

Description

A/C Relay

Note: The A/C Relay Command parameter may not change states when using this output control.

This function activates the A/C compressor relay. The normal commanded state of the A/C relay is None. The A/C compressor will turn ON/OFF when commanded ON/OFF. The system remains in the commanded state until cancelled by the scan tool. This output can also be monitored on the scan tool data parameter A/C Relay Command. The engine control module (ECM) will inhibit the operation of the A/C relay when the ambient air temperature is low.

Crankshaft Position Variation Learn

This function enables the engine control module (ECM) to learn the variations in the crankshaft position (CKP) system. The ECM will learn the variations once the following conditions are met:

    • Engine coolant temperature (ECT) is more than a predetermined value.
    • All the instructions on the scan tool have been completed.
    • Hold the accelerator pedal at wide open throttle (WOT) for 5 fuel cut-offs, as specified on the scan tool, then release accelerator pedal.

The ECM learns the variation values on the deceleration from fuel cut-off.

EGR Solenoid

Note: The EGR Position Sensor parameter may not properly change states when using this output control.

This function activates the exhaust gas recirculation (EGR) solenoid that controls EGR valve position. The normal commanded state is None. The system will increase or decrease the amount of EGR opening by 10 percent increments within a range of 0-100 percent. The EGR Position sensor parameter may not change states until commanded to 40 percent. This output can also be monitored on the scan tool data parameter EGR Position Sensor. The system remains in the commanded state until cancelled by the scan tool. If the engine is running, too much EGR will result in a rough idle and/or stalling.

EVAP Purge Solenoid

Note: 

   • This function may be disabled if there is an EVAP DTC set.
   • The EVAP Purge Solenoid Command parameter may not properly change states when using this output control.

This function controls the EVAP purge solenoid valve. The normal commanded state is None. The system will increase or decrease the amount of purge by changing the duty cycle of the purge valve in 10 percent increments within a range of 0-100 percent. The system remains in the commanded state until cancelled by the scan.

EVAP Vent Solenoid

Note: This function may be disabled if there is an EVAP DTC set.

This function controls the EVAP vent solenoid. The normal commanded state is None. When commanded ON, the vent valve switches to Not-venting. When commanded OFF, the vent valve switches to Venting. The system remains in the commanded state unless one of the following conditions occurs:

    • Cancelled by the scan tool
    • The fuel tank pressure (FTP) sensor exceeds a predetermined value.

EVAP Purge/Seal

Simultaneously activates the purge solenoid in 10 percent increments from 0 to 100 percent and the vent solenoid. The device control will be aborted and inhibited if the FTP sensor exceeds 19 mm Hg (10 in H2O).

Fan High Speed

This function operates one engine cooling fan at high speed by enabling the fan high speed relay. The normal commanded state of the relay is None. When commanded ON/OFF, the cooling fan turns ON/OFF. The system remains in the commanded state until cancelled by the scan tool. The ECM allows relay control when the following conditions are met:

    • The ignition is ON, with the engine OFF.
    • The engine is running.
    • The transmission must be in Park or Neutral.
    • The A/C request is OFF.
    • The engine coolant temperature is less than a predetermined value.

Fan Low Speed

This function operates one engine cooling fan at high speed by enabling the fan high speed relay. The normal commanded state of the relay is None. When commanded ON/OFF, the cooling fan turns ON/OFF. The system remains in the commanded state until cancelled by the scan tool. The ECM allows relay control when the following conditions are met:

    • The ignition is ON, with the engine OFF.
    • The engine is running.
    • The transmission must be in Park or Neutral.
    • The A/C request is OFF.
    • The engine coolant temperature is less than a predetermined value.

Fuel Injector Test

Note: DTCs may set when using this output control.

This function operates the selected fuel injector ON/OFF. The normal commanded state is None. The ECM enables or disables the fuel injector ON/OFF when the test is initiated. The fuel injector remains in the commanded state until cancelled by the scan tool. The scan tool initiates the test when the following conditions are met:

    • The engine is running.
    • The vehicle speed is 0 km/h (0 mph).

Fuel Pump Relay

Note: DTCs may set when using this output control.

This function controls the fuel pump relay. The normal commanded state is None. The scan tool initiates the test when the following conditions are met:

    • There are no vehicle speed sensor DTCs set.
    • The vehicle speed is 0 km/h (0 mph).

When commanded ON/OFF, the ECM turns the fuel pump relay ON/OFF. If the engine is running and the fuel pump relay is commanded OFF, the engine will stall. This output can also be monitored on the scan tool data parameter Fuel Pump Relay Command. The system remains in the commanded state until cancelled by the scan tool or the ECM detects a vehicle speed.

Engine Speed

This function controls the idle speed override in 25 RPM, 100 RPM, and 500 RPM increments, from the base idle speed to 1,400 RPM. The scan tool initiates the test when the following conditions are met:

    • The transmission is in park or neutral.
    • The engine speed is less than 1,000 RPM.

The engine speed will remain in the commanded state until cancelled by the scan tool.

IAC Motor Position

This function activates the idle air control (IAC) valve to change engine speed. The normal commanded state is None. The system will increase or decrease the amount of IAC opening by 5 percent increments within a range of 500-4,000 RPM. This output can also be monitored on the scan tool data parameter IAC Position. The system remains in the commanded state until cancelled by the tool.

IAC Reset

This function resets the IAC valve position and the learned values for the IAC system in the ECM.

IMT Valve

This function controls the intake manifold tuning (IMT) valve solenoid. The normal commanded state is None. When commanded ON/OFF, the ECM turns the IMT valve solenoid ON/OFF. The scan tool initiates the test when the following conditions are met:

    • There are no vehicle speed sensor DTCs set.
    • The vehicle speed is 0 km/h (0 mph).

The system remains in the commanded state until cancelled by the scan tool.

Malfunction Indicator Lamp

Note: The MIL Command parameter may not change states when using this output control.

This function controls the malfunction indicator lamp (MIL). The normal commanded state is None. When commanded ON/OFF, the ECM turns the malfunction indicator lamp (MIL) ON/OFF. This output can also be monitored on the scan tool data parameter MIL Command. The system remains in the commanded state until cancelled by the scan tool.

Throttle Position

This function controls the throttle valve in 10 percent increments. The scan tool initiates the test when the following conditions are met:

    • There are no vehicle speed sensor DTCs set.
    • The vehicle speed is 0 km/h (0 mph).
    • The ignition is ON, with the engine OFF.
    • The ECM is not commanding a throttle learn.

The system remains in the commanded state until cancelled by the scan tool.

Engine Control Module Scan Tool Information LDT

Table 1: Engine Control Module Scan Tool Data
Table 2: Engine Control Module (ECM) Scan Tool Output Controls

The Engine Control Module Scan Tool Data List contains all engine-related parameters that are available on the scan tool. This is a master list arranged in alphabetical order and not all the parameters listed are in every engine platform.

Use the Engine Scan Tool Data List only after the following is determined:

    • The Diagnostic System Check - Vehicle is completed.
    • No diagnostic trouble codes (DTCs)
    • On-board diagnostics are functioning properly

The scan tool values from a properly running engine may be used for comparison with the engine you are diagnosing. The Engine Scan Tool Data List represents values that would be seen on a normally running engine.

Note: A scan tool that displays faulty data should not be used. The scan tool concern should be reported to the manufacturer. Use of a faulty scan tool can result in misdiagnosis and unnecessary parts replacement.

Only the parameters listed below are referenced in this service manual for use in diagnosis.

Engine Control Module Scan Tool Data

Parameter

System State

Expected Value

Description

Base Operating Conditions: Engine Idling/Radiator Hose Hot/Park or Neutral/Closed Loop

5 Volt Reference 1 or 2

Ignition ON

5 Volts

This parameter displays the output voltage from the 5-volt reference circuit to the control module. This parameter only supports one 5-volt reference output from the control module.

A/C High Side Pressure

A/C OFF

0-5 Volts

This parameter displays the voltage from the A/C high side pressure sensor signal circuit to the control module.

A/C ON

0-5 Volts

A/C High Side Pressure

A/C OFF

450-650 kPa (65-95 psi)

This parameter displays the pressure from the A/C high side pressure sensor signal circuit to the control module.

A/C ON

650-800 kPa (95-105 psi)

A/C Relay Command

A/C ON

On

This parameter displays the state of the air conditioning (A/C) clutch relay control circuit as commanded by the control module.

A/C Request Signal

A/C ON

Yes

This parameter displays the state of the A/C request input to the control module from the heating, ventilation, and air conditioning (HVAC) controls.

Air Flow Calculated

--

3-6 g/s

This parameter displays the calculated air flow into the engine that is based on manifold absolute pressure. The calculation is used in several diagnostics to determine when to run the diagnostics.

Air Fuel Ratio

--

Ratio 14.7:1

This parameter displays the air to fuel ratio based on the oxygen sensor inputs. The engine control module (ECM) uses the fuel trims to adjust fueling in order to attempt to maintain an air fuel ratio of 14.7:1.

APP Indicated Angle

--

Varies

This parameter displays the angle of the accelerator pedal position (APP) as calculated by the control module using the signals from the APP sensors.

APP Sensor 1 or 2

--

Varies

This parameter displays the actual percentage of each APP sensor signal circuit as measured by the control module.

APP Sensor 1 or 2

--

Agree

This parameter displays Disagree if the control module detects the signal voltage from APP sensor 1 is not in correct relationship to APP sensor 2. The scan tool displays Agree under the normal operating conditions.

BARO

--

65-104 kPa (8-16 psi) - Varies with altitude

This parameter displays the barometric pressure. The control module uses the barometric pressure sensor input for fuel control to compensate for altitude differences.

Case Diagnostic Learning

--

Learned

This parameter displays Learned if the control module has completed the CKP System Variation Learn Procedure.

Case Learned Cyl. 1-4

--

Counts

This parameter displays the CKP Learn offset in counts between cylinders.

Catalytic Converter Protection Active

--

No

This parameter displays if the control module is commanding catalytic converter protection.

Cmmd. A/F Equivalence Ratio

--

Ratio 1.0:1

This parameter displays the air to fuel ratio based on throttle state. The control module changes the ratio for acceleration or deceleration.

CMP Active Counter

--

1-3 Counts

This parameter displays the camshaft position (CMP) active counts. If the control module does not detect a signal from the CMP sensor, the counter will not increment.

Cruise Control Active

Cruise Control ON

Yes

This parameter displays the status of the cruise control system as determined by the control module.

Cruise Disengage 1-5 History

--

Varies

This parameter displays the history of the action taking with the cruise system.

Cruise Lamp Command

Cruise Control ON

On

This parameter displays the state of the cruise lamp to the instrument panel (IP) cluster as requested by the control module.

Cruise ON/OFF Switch

Cruise Control ON

Yes

This parameter displays the state of the ON/OFF switch input to the control module.

Cruise Resume/Accel. Switch

Cruise Resume/Accel. Switch ON

Active

This parameter displays the state of the Resume/Accel switch input to the control module from the cruise control system.

Cruise Set/Coast Switch

Cruise Set/Coast Switch ON

Active

This parameter displays the state of the Set/Coast switch input to the control module from the cruise control system.

Decel Fuel Cut Off

--

Inactive

This parameter displays the status of the operating mode of the control module used to turn off the fuel injectors during certain deceleration conditions.

Desired Exhaust CMP

--

Degrees

This parameter displays the desired exhaust camshaft angle in degrees as commanded by the control module.

Desired Idle Speed

--

750-950 RPM

This parameter displays the desired engine idle speed as commanded by the control module.

Desired Intake CMP

--

Degrees

This parameter displays the desired intake camshaft angle in degrees as commanded by the control module.

Distance Since DTC Cleared

--

Varies

This parameter displays the mileage that has elapsed since the DTC cleared.

ECT Sensor

--

-39 to +140°C ( -38 to +284°F)

This parameter displays the temperature of the engine coolant based on input to the control module from the engine coolant temperature (ECT) sensor.

Engine Load

Engine Idling

25-40%

This parameter displays the calculated engine load in percent based on inputs to the control module from various engine sensors.

Engine speed at 2,500 RPM

25-40%

Engine Run Time

Engine Operating

0:00:00

Increments when the engine is operating

This parameter displays the time elapsed since the engine was started.

Engine Speed

Engine Cranking

Greater than 60 RPM

This parameter displays the speed of the engine crankshaft rotation from information received from the crankshaft position (CKP) sensor. If there is a CKP sensor DTC, the ECM calculates the engine speed from one of the camshaft position (CMP) sensors.

Engine Idling

Approximately 750-950 RPM

EVAP Purge Solenoid Command

--

0-100%

This parameter displays the on-time or duty cycle of the EVAP canister purge solenoid commanded by the control module. Zero percent indicates no purge. One hundred percent indicates full purge.

Exhaust CMP Angle

--

Degrees

This parameter displays the actual exhaust camshaft position in degrees.

Exhaust CMP Command

--

0-100%

This parameter displays the exhaust camshaft position in percent of range as commanded by the control module.

Fail Counter

--

Counts

This parameter displays the number of times a DTC failed

Fan High Speed Command

Fan High Speed ON

On

This parameter displays the control module commanded state of the fan relay control circuit.

Fan Low Speed Command

Fan Low Speed ON

On

This parameter displays the control module commanded state of the fan relay control circuit.

Fuel Level Gage Command

--

Varies

This parameter displays the control module commanded state of the fuel gage control circuit.

Fuel Level Sensor

--

0-100%

This parameter displays the amount of fuel in the fuel tank in percent of range, as calculated by the control module.

Fuel Level Sensor

--

0-5 Volts

This parameter displays the voltage signal received by the control module from the fuel level sensor.

Fuel Pump Relay Command

Ignition ON, engine OFF

Fuel pump on for 2 seconds

This parameter displays the control modules commanded state of the fuel pump relay control circuit.

Engine idling

On

Fuel Trim Cell

--

Cell Number

This parameter displays what fuel trim cell that is currently active.

Fuel Trim Learned

--

Enabled

This parameter displays Enabled when conditions are appropriate for enabling long term fuel trim corrections. This indicates that the long term fuel trim is adapting continuing amounts of short term fuel trim. If the scan tool displays Disabled, then long term fuel trim will not respond to changes in short term fuel trim.

GEN L-Terminal Signal Command

--

0-100%

This parameter displays the control modules commanded state of the voltage regulator on the generator.

Generator F-Terminal Signal

--

0-100%

This parameter displays the amount of generator on-time as commanded by the control module. The higher the percentage the greater the generator output.

HO2S 1 or HO2S 2 Heater

--

Varies

This parameter displays the amperage of the HO2S heater commanded by the control module.

IAT Sensor

--

-39° to +140°C

(-38° to +284°F)

This parameter displays the temperature of the air entering the air induction system based on input to the control module from the intake air temperature (IAT) sensor.

Ignition 1 Signal

--

B+

This parameter displays B+ when the control module detects a voltage at the ignition 1 input terminal.

Injector PWM Average

--

0-9 ms

This parameter displays the average pulse width of the fuel injectors as determined by the control module.

Intake CMP Angle

--

Degrees

This parameter displays the actual intake camshaft position in degrees.

Intake CMP Command

--

0-100%

This parameter displays the intake camshaft position in percent of range as commanded by the control module.

Knock Retard

--

Degrees

This parameter indicates the amount of spark advance the control module removes from the ignition control (IC) spark advance in response to the signal from the knock sensors.

KS Active Counter

--

Counts

This parameters displays the number of times the control module detects activity from the knock sensor.

Long Term FT

--

0-2%

This parameter displays the commanded Long Term Fuel Trim correction by the control module.

Long Term FT Average

--

0%

This parameter displays the commanded Long Term Fuel Trim correction by the control module.

Loop Status

--

Closed Loop

This parameter displays the state of the fuel control system as commanded by the control module. Closed Loop operation indicates that the control module is controlling the fuel delivery based off the oxygen sensors input signal. In Open Loop operation the control module ignores the oxygen sensor input signal and bases the amount of fuel to be delivered on other sensor inputs.

Low Fuel Lamp Command

Low Fuel Lamp Command ON

On

This parameter displays the control modules commanded state of the low fuel lamp.

MAP Sensor

--

32-50 kPa

This parameter displays the pressure from the MAP sensor to the control module

MAP Sensor

--

0-5 Volts

This parameter displays the signal voltage from the MAP sensor to the control module.

MIL Command

MIL Command ON

On

This parameter displays the commanded state of the malfunction indicator lamp (MIL) control circuit by the control module.

Mileage Since First Failure

--

Varies

This parameter displays the mileage that has elapsed since the first emission failure.

Mileage Since Last Failure

--

Varies

This parameter displays the mileage that has elapsed since the last emission failure.

Misfire Current Cyl. 1-4

--

0-255 Counts

This parameter displays the number of misfires that have been detected during the last 200 cylinder firing events. The counters may normally display some activity, but the activity should be nearly equal for all of the cylinders, and in low numbers.

Misfire Detects Rough Road

Rough Road Detected

Yes

This parameter displays the detection of a rough road during misfire detection by the control module.

Misfire History Cyl. 1-4

--

0-255 Counts

The misfire history counters display the total level of misfire that has been detected on each cylinder. The misfire history counters will not update or show any activity until a misfire DTC P0300 has become active. The misfire history counters will update every 200 cylinder firing events.

Not Run Counter

--

Counts

This parameter displays the number of times a DTC does not run.

O2S/HO2S 1 or 2

--

Varies 400-800 mV

This parameter displays the voltage output from the H/O2S to the control module. A lower voltage indicates a lean exhaust, while a higher voltage indicates a rich exhaust.

O2S/HO2S 1 Ready

--

Yes

This parameter displays that the HO2S 1 is at operating temperature.

Pass Counter

--

Counts

This parameter displays the number of times a DTC passed.

PNP Switch

--

Park/Neutral

This parameter displays whether the transmission range selector is in park/neutral or in gear.

Power Enrichment

--

Inactive

This parameter displays the status of the operating mode of the control module used to increase fuel delivery during certain acceleration conditions.

Rich/Lean to Lean/Rich Ratio Sensor 1

--

Counts

This parameter displays the oxygen sensor rich/lean to lean/rich ratio. The rich/lean average is divided by the lean/rich average in order to determine the oxygen sensor ratio.

Rich/Lean to Transition Sensor 1

--

Counts

This parameter displays the oxygen sensor rich/lean and lean/rich switches. A switch is when the oxygen sensor voltage goes above 450 mV and below 450 mV.

Reduced Engine Power

--

No

This parameter displays the status of the operating mode of the control module used to reduce engine power to prevent catalytic converter or engine damage or due to a Throttle Actuator Control (TAC) system failure.

Rough Road Sensor

--

0-5 Volts

This parameter displays the voltage from the rough road sensor.

Rough Road Signal-ABS

--

0-5 Volts

This parameter displays the voltage from the ABS module for the rough road signal.

Short Term FT Avg.

--

-3% to +3%

This parameter displays the short-term correction to the fuel delivery by the control module in response to oxygen sensor. If the oxygen sensor indicates a lean air/fuel mixture, the control module will add fuel increasing the short term fuel trim above 0. If the oxygen sensor indicates a rich air/fuel mixture, the control module will reduce fuel decreasing the short term fuel trim below 0.

Short Term FT

--

-3% to +3%

This parameter displays the short-term correction to the fuel delivery by the control module in response to oxygen sensor. If the oxygen sensor indicates a lean air/fuel mixture, the control module will add fuel increasing the short term fuel trim above 0. If the oxygen sensor indicates a rich air/fuel mixture, the control module will reduce fuel decreasing the short term fuel trim below 0.

Spark

--

-20 to +40Degrees

This parameter displays the amount of spark advance the control module is commanding on the ignition control circuits. The control module determines the desired advance.

Start Up ECT

--

-39° to +140°C

(-38° to +284°F)

This parameter displays the temperature of the engine coolant on start up based on input to the control module from the ECT sensor.

Start Up IAT

--

-39° to +140°C

(-38° to +284°F)

This parameter displays the temperature of the intake air at start in the air induction system based on input to the control module from the IAT sensor.

SVS Lamp Command

SVS Lamp Command ON

On

This parameter displays the control modules commanded state of the service vehicle soon lamp.

TAC Motor Command

TAC Motor Command ON

Varies

This parameter displays the percentage of the commanded state of the TAC motor by the control module.

TCC Enable Solenoid Command

TCC Enable Solenoid Command ON

On

This parameter displays the control module commanded state of the TCC solenoid.

Throttle Plate at Idle

--

Yes

This parameter displays whether the throttle plate at idle or not as calculated by the control module using information from the throttle position (TP) sensor. The scan tool will display Yes for the throttle plate to be at idle. The scan tool will display No when the throttle plate is opened.

Total Misfire

--

Counts

This parameter displays the total number of cylinder firing events that the control module detected as misfires for the last 200 crankshaft revolution sample period.

TP Desired Angle

--

Varies

This parameter displays the desired TP angle commanded by the control module.

TP Indicated Angle

--

Varies

This parameter displays the actual TP angle indicated by the control module using information from the two TP sensors.

TP Sensor 1 or 2

--

Varies

This parameter displays the percent of throttle opening as calculated by the control module using information from the throttle position (TP) sensor.

TP Sensor 1 or 2

--

Agree

This parameter displays Disagree when the control module detects that TP sensor 1 voltage signal is not within the correct relationship to TP sensor 2. The scan tool displays Agree under the normal operating conditions.

Transmission Gear Position Signal

--

Park/Neutral

This parameter displays the position of the transmission gear selector that is transmitted over the serial data circuit from the transmission control module (TCM).

TWC Temperature Calculated

--

Varies

This parameter displays the catalytic converter temperature as calculated by the control module.

Vehicle Security Status

--

Disabled

This parameter displays the status of the vehicle theft deterrent system. The normal parameter display for the theft deterrent system is Disabled. If a condition exists with the theft deterrent system the parameter will display Enabled and the vehicle will not start.

Vehicle Speed Sensor

--

0 Km/h

0 mph

This parameter displays the speed of the vehicle as calculated by the transmission control module (TCM) from information received from the vehicle speed sensor (VSS).

Warm-ups Since DTC Cleared

--

Counts

This parameter displays the number of warm-ups since the DTC was cleared.

Wheel/Vehicle Speed Input

--

0 Km/h

0 mph

This parameter displays the speed of the vehicle as calculated by the control module from information received from the vehicle speed sensor (VSS) or wheel speed sensor depending on application.

Engine Control Module (ECM) Scan Tool Output Controls

Output Control

Description

A/C Relay

Note: The A/C Relay Command parameter may not change states when using this output control.

This function activates the A/C compressor relay. The normal commanded state of the A/C relay is None. The A/C compressor will turn ON/OFF when commanded ON/OFF. The system remains in the commanded state until cancelled by the scan tool. This output can also be monitored on the scan tool data parameter A/C Relay Command. The engine control module (ECM) will inhibit the operation of the A/C relay when the ambient air temperature is low.

Crankshaft Position Variation Learn

This function enables the engine control module (ECM) to learn the variations in the crankshaft position (CKP) system. The ECM will learn the variations once the following conditions are met:

    • Engine coolant temperature (ECT) is more than a predetermined value.
    • All the instructions on the scan tool have been completed.
    • Hold the accelerator pedal at wide open throttle (WOT) for 5 fuel cut-offs, as specified on the scan tool, then release accelerator pedal.

The ECM learns the variation values on the deceleration from fuel cut-off.

Desired Intake/Exhaust CMP

This function controls the selected camshaft actuator solenoid. The normal commanded state is NONE. The system will increase or decrease the angle of the selected camshaft in 5 degree increments up to 40 crankshaft degrees. The scan tool initiates the test when the following conditions are met:

    • The vehicle speed is 0 km/h (0 mph).
    • The transmission is in park or neutral.
    • The engine speed is at idle.

The system remains in the commanded state until cancelled by the scan tool.

Desired Intake/Exhaust CMP

This function controls the selected camshaft actuator solenoid. The normal commanded state is NONE. When commanded ON/OFF, the ECM turns the camshaft actuator solenoid ON/OFF. The scan tool initiates the test when the following conditions are met:

    • The ignition is ON with the engine OFF.
    • No engine speed is detected.

The system remains in the commanded state until cancelled by the scan tool.

EVAP Purge Solenoid

Note: 

   • This function may be disabled if there is an EVAP DTC set.
   • The EVAP Purge Solenoid Command parameter may not properly change states when using this output control.

This function controls the EVAP purge solenoid valve. The normal commanded state is None. The system will increase or decrease the amount of purge by changing the duty cycle of the purge valve in 10 percent increments within a range of 0-100 percent. The system remains in the commanded state until cancelled by the scan.

Fan High Speed

This function operates one engine cooling fan at high speed by enabling the fan high speed relay. The normal commanded state of the relay is None. When commanded ON/OFF, the cooling fan turns ON/OFF. The system remains in the commanded state until cancelled by the scan tool. The ECM allows relay control when the following conditions are met:

    • The ignition is ON, with the engine OFF.
    • The engine is running.
    • The transmission must be in Park or Neutral.
    • The A/C request is OFF.
    • The engine coolant temperature is less than a predetermined value.

Fan Low Speed

This function operates one engine cooling fan at high speed by enabling the fan high speed relay. The normal commanded state of the relay is None. When commanded ON/OFF, the cooling fan turns ON/OFF. The system remains in the commanded state until cancelled by the scan tool. The ECM allows relay control when the following conditions are met:

    • The ignition is ON, with the engine OFF.
    • The engine is running.
    • The transmission must be in Park or Neutral.
    • The A/C request is OFF.
    • The engine coolant temperature is less than a predetermined value.

Fuel Injector Test

Note: DTCs may set when using this output control.

This function operates the selected fuel injector ON/OFF. The normal commanded state is None. The ECM enables or disables the fuel injector ON/OFF when the test is initiated. The fuel injector remains in the commanded state until cancelled by the scan tool. The scan tool initiates the test when the following conditions are met:

    • The engine is running.
    • The vehicle speed is 0 km/h (0 mph).

Fuel Pump Relay

Note: DTCs may set when using this output control.

This function controls the fuel pump relay. The normal commanded state is None. The scan tool initiates the test when the following conditions are met:

    • There are no vehicle speed sensor DTCs set.
    • The vehicle speed is 0 km/h (0 mph).

When commanded ON/OFF, the ECM turns the fuel pump relay ON/OFF. If the engine is running and the fuel pump relay is commanded OFF, the engine will stall. This output can also be monitored on the scan tool data parameter Fuel Pump Relay Command. The system remains in the commanded state until cancelled by the scan tool or the ECM detects a vehicle speed.

Engine Speed

This function controls the idle speed override in 25 RPM, 100 RPM, and 500 RPM increments, from the base idle speed to 1,400 RPM. The scan tool initiates the test when the following conditions are met:

    • The transmission is in park or neutral.
    • The engine speed is less than 1,000 RPM.

The engine speed will remain in the commanded state until cancelled by the scan tool.

Malfunction Indicator Lamp

Note: The MIL Command parameter may not change states when using this output control.

This function controls the malfunction indicator lamp (MIL). The normal commanded state is None. When commanded ON/OFF, the ECM turns the malfunction indicator lamp (MIL) ON/OFF. This output can also be monitored on the scan tool data parameter MIL Command. The system remains in the commanded state until cancelled by the scan tool.

Throttle Position

This function controls the throttle valve in 10 percent increments. The scan tool initiates the test when the following conditions are met:

    • There are no vehicle speed sensor DTCs set.
    • The vehicle speed is 0 km/h (0 mph).
    • The ignition is ON, with the engine OFF.
    • The ECM is not commanding a throttle learn.

The system remains in the commanded state until cancelled by the scan tool.

Engine Control Module Scan Tool Information LMU

Table 1: Engine Control Module Scan Tool Data
Table 2: Engine Control Module (ECM) Scan Tool Output Controls

The Engine Control Module Scan Tool Data List contains all engine-related parameters that are available on the scan tool. This is a master list arranged in alphabetical order and not all the parameters listed are in every engine platform.

Use the Engine Scan Tool Data List only after the following is determined:

    • The Diagnostic System Check - Vehicle is completed.
    • No diagnostic trouble codes (DTCs)
    • On-board diagnostics are functioning properly

The scan tool values from a properly running engine may be used for comparison with the engine you are diagnosing. The Engine Scan Tool Data List represents values that would be seen on a normally running engine.

Note: A scan tool that displays faulty data should not be used. The scan tool concern should be reported to the manufacturer. Use of a faulty scan tool can result in misdiagnosis and unnecessary parts replacement.

Only the parameters listed below are referenced in this service manual for use in diagnosis.

Engine Control Module Scan Tool Data

Parameter

System State

Expected Value

Description

Base Operating Conditions: Engine Idling/Radiator Hose Hot/Park or Neutral/Closed Loop

Actual Main Throttle Idle Actuator

--

Steps

This parameter displays the engine control module (ECM) command for the throttle plate position in steps. The higher the number of steps, the greater the commanded opening of the throttle plate.

A/C High Side Pressure

A/C OFF

0-5 Volts

This parameter displays the voltage from the A/C high side pressure sensor signal circuit to the control module.

A/C ON

0-5 Volts

A/C High Side Pressure

A/C OFF

500-2,200 kPa (72-319 psi)

This parameter displays the pressure from the A/C high side pressure sensor signal circuit to the control module.

A/C ON

300-1,200 kPa (43-174 psi)

A/C Relay Command

A/C ON

On

This parameter displays the state of the air conditioning (A/C) clutch relay control circuit as commanded by the control module.

BARO

--

65-104 kPa (8-16 psi) - Varies with altitude

This parameter displays the barometric pressure. The control module uses the barometric pressure sensor input for fuel control to compensate for altitude differences.

Desired Idle Speed

--

800 RPM

This parameter displays the desired engine idle speed as commanded by the control module.

Desired Main Throttle Idle Actuator

--

Steps

This parameter displays the desired throttle plate position as commanded by the control module.

DTC Set This Ignition

--

No

This parameter displays Yes if a DTC set on the current ignition cycle.

ECT Sensor

--

0-5 Volts

This parameter displays the voltage of the engine coolant based on input to the control module from the engine coolant temperature (ECT) sensor.

ECT Sensor

--

-40° to +130°C (-40° to +266°F)

This parameter displays the temperature of the engine coolant based on input to the control module from the engine coolant temperature (ECT) sensor.

EC Ignition Relay Command

Ignition ON

ON

This parameter displays the state of the control circuit for main relay as commanded by the control module.

EGR Position Sensor

--

0.6-0.75 Volts

This parameter displays the actual EGR pintle position in volts.

EGR Solenoid Command

--

0%

This parameter displays the state of the control circuit for EGR solenoid as commanded by the control module.

Engine Load

Engine Idling

20-30%

This parameter displays the calculated engine load in percent based on inputs to the control module from various engine sensors.

Engine speed at 2,500 RPM

10-20%

Engine Speed

Engine Cranking

Greater than 60 RPM

This parameter displays the speed of the engine crankshaft rotation from information received from the crankshaft position (CKP) sensor. If there is a CKP sensor DTC, the ECM calculates the engine speed from one of the camshaft position (CMP) sensors.

Engine Idling

Approximately 650-900 RPM

Engine Running State

--

Idling

This parameter displays the state of the engine.

Engine Run Time

--

0:00:00 Increments when the engine is running

This parameter displays the time elapsed since the engine was started.

EVAP Purge Solenoid Command

--

0-100%

This parameter displays the on-time or duty cycle of the EVAP canister purge solenoid commanded by the control module. Zero percent indicates no purge. One hundred percent indicates full purge.

FC Relay 1 Command

Fan Low Commanded ON

ON

This parameter displays the control module commanded state of the fan relay control circuit.

FC Relay 2 Command

Fan High Commanded ON

ON

This parameter displays the control module commanded state of the fan relay control circuit.

Fuel Gage Control

--

0-100%

This parameter displays control module commanded state of the fuel gage control circuit.

Fuel Level Sensor

--

0-100%

This parameter displays the amount of fuel in the fuel tank in percent of range, as calculated by the control module.

Fuel Level Sensor

--

0-5 Volts

This parameter displays the voltage signal received by the control module from the fuel level sensor.

Fuel Pump Relay Command

Ignition ON, engine OFF

Fuel pump on for 2 seconds

This parameter displays the control modules commanded state of the fuel pump relay control circuit.

Engine idling

On

Fuel Tank Pressure Sensor

--

0-5 Volts

This parameter displays the voltage signal received by the control module from the fuel tank pressure (FTP) sensor.

Fuel Tank Pressure Sensor

--

kPa/PSI

This parameter displays the pressure/vacuum inside the fuel tank. A negative value indicates a vacuum, while a positive value indicates a pressure.

HO2S 1 or 2

--

Varies 400-800 mV

This parameter displays the voltage output from the H/O2S to the control module. A lower voltage indicates a lean exhaust, while a higher voltage indicates a rich exhaust.

HO2S 1 and 2 Heater Command

--

0-100%

This parameter displays the commanded state of the heater control circuit as commanded by the control module.

IAT Sensor

--

-39° to +140°C

(-38° to +284°F)

This parameter displays the temperature of the air entering the air induction system based on input to the control module from the intake air temperature (IAT) sensor.

IAT Sensor

--

0-5 Volts

This parameter displays the IAT sensor voltage.

Ignition 1 Signal

--

Volts

This parameter displays B+ when the control module detects a voltage at the ignition 1 input terminal.

Injector PWM Average

--

0-9 ms

This parameter displays the average pulse width of the fuel injectors as determined by the control module.

Intake Manifold Runner Control (IMRC) Solenoid

--

Open

This parameter displays the control modules commanded state of the IMT Valve solenoid.

ISC Actuator

--

0-100%

This parameter displays the ECM command for the idle speed control (ISC) motor position in percentage. The higher the number, the greater the commanded idle speed reads. The ISC responds to changes in the engine load in order to maintain the desired idle speed.

Knock Sensor

--

0-5 Volts

This parameters displays the voltage input to the control module from the knock sensor (KS).

Long Term FT

--

0%

This parameter displays the commanded Long Term Fuel Trim correction by the control module.

Long Term FT Part Throttle

--

0%

This parameter displays the commanded Long Term Fuel Trim correction by the control module for part throttle conditions.

Long Term FT Idle

--

0%

This parameter displays the commanded Long Term Fuel Trim correction by the control module for idle conditions.

Loop Status

--

Closed Loop

This parameter displays the state of the fuel control system as commanded by the control module. Closed Loop operation indicates that the control module is controlling the fuel delivery based off the oxygen sensors input signal. In Open Loop operation the control module ignores the oxygen sensor input signal and bases the amount of fuel to be delivered on other sensor inputs.

MAP Sensor

--

32-40 kPa

This parameter displays the pressure from the MAP sensor to the control module.

MAP Sensor

--

0-5 Volts

This parameter displays the signal voltage from the MAP sensor to the control module.

MIL Command

--

Off

This parameter displays the commanded state of the malfunction indicator lamp (MIL) control circuit by the control module.

PNP Switch

--

Park/Neutral

This parameter displays whether the transmission range selector is in park/neutral or in gear.

Rear Wheel Speed Sensor

--

0-5 Volts

This parameter displays the speed of the vehicle as calculated by the control module from information received from the vehicle speed sensor (VSS) or wheel speed sensor depending on application.

Right Rear Wheel Speed Sensor

--

Km/h

mph

This parameter displays the speed of the vehicle as calculated by the control module from information received from the right rear wheel speed sensor.

Short Term FT

--

-3% to +3%

This parameter displays the short-term correction to the fuel delivery by the control module in response to oxygen sensor. If the oxygen sensor indicates a lean air/fuel mixture, the control module will add fuel increasing the short term fuel trim above 0. If the oxygen sensor indicates a rich air/fuel mixture, the control module will reduce fuel decreasing the short term fuel trim below 0.

Spark

--

-20 to +40 Degrees

This parameter displays the amount of spark advance the control module is commanding on the ignition control circuits. The control module determines the desired advance.

TP Sensor

--

4.0-4.5 Volts

This parameter displays the actual voltage on the TP sensor signal circuit as measured by the control module.

TP Sensor

--

3-5%

This parameter displays the percent of throttle opening as calculated by the control module using information from the throttle position (TP) sensor.

Transmission Gear Selector Signal

--

Park/Neutral

This parameter displays the position of the transmission gear selector that is transmitted over the serial data circuit from the transmission control module (TCM).

Vehicle Speed Sensor

--

Km/h

mph

This parameter displays the speed of the vehicle as calculated by the transmission control module (TCM) from information received from the vehicle speed sensor (VSS).

Engine Control Module (ECM) Scan Tool Output Controls

Output Control

Description

A/C Relay

This function controls the A/C compressor relay. When commanded ON, the A/C compressor will cycle ON/OFF for 3-5 seconds.

EGR Solenoid

Note: This function is only allowed with the ignition ON, engine OFF.

This function controls the exhaust gas recirculation (EGR) solenoid. When commanded ON, the EGR solenoid will cycle from 0-100 percent for 3-5 seconds. This output can also be monitored on the scan tool by observing the EGR Position Sensor data parameter.

Engine Controls Ignition Relay

Note: This function is only allowed with the ignition ON, engine OFF.

This function controls the engine control ignition relay or MAIN relay. When commanded ON, the engine control ignition relay will cycle ON/OFF for 3-5 seconds.

EVAP Purge Solenoid

This function controls the evaporative emission (EVAP) purge solenoid. When commanded ON, the EVAP purge solenoid will cycle ON/OFF for 3-5 seconds. This output can also be monitored on the scan tool by observing the EVAP Purge Solenoid Command data parameter.

Fan High

This function controls the high speed cooling fan relay. When commanded ON, the cooling fan will turn ON at high speed for 5 seconds.

Fan Low

This function controls the low speed cooling fan relay. When commanded ON, the cooling fan will turn ON at low speed for 5 seconds.

Fuel Pump Relay

Note: This function is only allowed with the ignition ON, engine OFF.

This function controls the fuel pump relay. When commanded ON, the fuel pump relay will cycle ON/OFF for 3-5 seconds.

Idle Learn Reset

This function resets the base idle value learned by the engine control module (ECM).

ISC Actuator

Note: This function is only allowed with the ignition ON, engine OFF.

This function controls the idle speed control (ISC) actuator. The ECM actuates the ISC actuator for 3-5 seconds when commanded ON. This output can also be monitored on the scan tool by observing the TP Sensor data parameter.

Malfunction Indicator Lamp

This function controls the malfunction indicator lamp (MIL). When commanded ON with the engine running, the ECM turns the (MIL) ON/OFF for 3-5 seconds. When commanded OFF with the ignition ON, engine OFF, the ECM turns the MIL ON/OFF for 3-5 seconds.

Engine Control Module Scan Tool Information LXV

Table 1: Engine Control Module Scan Tool Data
Table 2: Engine Control Module (ECM) Scan Tool Output Controls

The Engine Control Module Scan Tool Data List contains all engine-related parameters that are available on the scan tool. This is a master list arranged in alphabetical order and not all the parameters listed are in every engine platform.

Use the Engine Scan Tool Data List only after the following is determined:

    • The Diagnostic System Check - Vehicle is completed.
    • No diagnostic trouble codes (DTCs)
    • On-board diagnostics are functioning properly

The scan tool values from a properly running engine may be used for comparison with the engine you are diagnosing. The Engine Scan Tool Data List represents values that would be seen on a normally running engine.

Note: A scan tool that displays faulty data should not be used. The scan tool concern should be reported to the manufacturer. Use of a faulty scan tool can result in misdiagnosis and unnecessary parts replacement.

Only the parameters listed below are referenced in this service manual for use in diagnosis.

Engine Control Module Scan Tool Data

Parameter

System State

Expected Value

Description

Base Operating Conditions: Engine Idling/Radiator Hose Hot/Park or Neutral/Closed Loop

5 Volt Reference 1, 2, 3, or 4

Ignition ON

5 Volts

This parameter displays the voltage sensed on the 5-volt reference circuits at the control module. The scan tool will display a higher value at higher voltage. The scan tool will display a lower value at lower voltage.

5 Volt Reference 1, 2, 3, or 4

Ignition ON

OK

This parameter displays OK if there is no 5-volt reference circuit condition. If the circuit is shorted to ground or shorted to B+, fault is displayed.

A/C Disengage 1-8 History

A/C ON

Reason for A/C Disengagement

The parameter displays the last 8 air conditioning (A/C) compressor disengage reasons. The scan tool displays None, A/C Pressure, Engine Speed, Batt Voltage, Anti Stall, RPM Unstable, WOT, Launch Perf., or Coolant Hot.

A/C High Side Pressure

A/C OFF

0.75-1.5 Volts*

This parameter displays the voltage from the A/C high side pressure sensor signal circuit to the control module.

*Varies with temperature and relative humidity.

A/C ON

1.3-2.5 Volts*

A/C High Side Pressure

A/C OFF

450-650 kPa (65-95 psi)

This parameter displays the pressure from the A/C high side pressure sensor signal circuit to the control module.

*Varies with temperature and relative humidity.

A/C ON

Engine Speed at 2000 RPM

1117-2350 kPa* (162-341 psi)*

A/C Off For WOT

A/C ON

No

This parameter displays whether the control module is commanding the A/C compressor clutch relay OFF for wide open throttle (WOT).

A/C Pressure Disable

A/C ON

No

This parameter displays whether the A/C pressure is out of range for normal operation as determined by the control module.

A/C Relay Ckt Open Test Status

A/C ON

Not Run

This parameter displays the state of the air conditioning (A/C) clutch relay control circuit. The scan tool displays OK , Fault, or Not Run. OK indicates that no circuit faults are detected during the current test.

A/C Relay Ckt Short Gnd Test Status

A/C ON

Not Run

This parameter displays the state of the air conditioning (A/C) clutch relay control circuit. The scan tool displays OK , Fault, or Not Run. OK indicates that no circuit faults are detected during the current test.

A/C Relay Ckt Short Volts Test Status

A/C ON

OK

This parameter displays the state of the air conditioning (A/C) clutch relay control circuit. The scan tool displays OK , Fault, or Not Run. OK indicates that no circuit faults are detected during the current test.

A/C Relay Command

A/C ON

On

This parameter displays the state of the air conditioning (A/C) clutch relay control circuit as commanded by the control module.

A/C Request Signal

A/C ON

Yes

This parameter displays the state of the A/C request input to the control module from the heating, ventilation, and air conditioning (HVAC) controls.

Ambient Air Temp.

--

°C °F

Varies

This parameter displays the surrounding air temperature, at any given altitude.

APP Indicated Angle

Accelerator pedal not actuated

0%

This parameter displays the angle of the accelerator pedal position (APP) as calculated by the control module using the signals from the APP sensors.

Accelerator pedal fully actuated

100%

APP Sensor 1

Accelerator pedal not actuated

0.88-1.08 V

This parameter displays the actual voltage on the accelerator pedal position (APP) Sensor 1 signal circuit as measured by the control module.

Accelerator pedal fully actuated

4.17-4.37 V

APP Sensor 2

Accelerator pedal not actuated

0.39-0.59 V

This parameter displays the actual voltage on the accelerator pedal position (APP) Sensor 2 signal circuit as measured by the control module.

Accelerator pedal fully actuated

2.02-2.22 V

APP Sensor 1 2

--

Agree

This parameter displays the results of a control module test that compares the signals from the APP sensors 1 and 2. The scan tool will display Agree or Disagree. Agree indicates that APP sensor 1 and APP sensor 2 voltages correspond to the same accelerator pedal position. Disagree indicates that APP sensor 1 and APP sensor 2 voltages correspond to different accelerator pedal positions.

APP Sensors

--

0 %

This parameter displays the average of the APP sensors as calculated by the throttle actuator control (TAC) module. The APP average is a range of values indicating a low percentage when the accelerator pedal is not depressed to a high percentage when the accelerator pedal is fully depressed.

BARO

--

65-104 kPa (8-16 psi) - Varies with altitude

This parameter displays the barometric pressure. The control module uses the barometric pressure sensor input for fuel control to compensate for altitude differences.

BPP Circuit Signal

--

Learned

This parameter displays the serial data message of the brake signal from the electronic brake and traction control module (EBTCM).

Calc. TWC Temp.

--

°C °F

Varies

This parameter displays the catalytic converter temperature as calculated by the control module.

Catalyst Monitor Complete This Ignition

--

Yes / No

This parameter displays the monitor completion status during the current driving/monitoring cycle.

Catalyst Monitor Enabled This Ignition

--

Yes / No

This parameter displays the monitor enable status during the current driving/monitoring cycle.

Catalytic Converter Protection Active

--

No

This parameter displays if the control module is commanding catalytic converter protection.

CKP Active Counter

--

Incrementing

This parameter displays an incrementing counter when the control module receives a signal from the crankshaft position sensor (CKP).

CKP Resync Counter

--

Varies

This parameter displays the number of times the control module re-syncs with the CKP sensor.

CKP Sensor

--

Engine Speed

This parameter displays the engine speed as calculated by the control module using the signal from the CKP sensor.

Cmmd. A/F Equivalence Ratio

--

Ratio 1.0:1

This parameter displays the air to fuel ratio based on throttle state. The control module changes the ratio for acceleration or deceleration.

CMP Sensor

--

Engine Speed

This parameter displays the speed of the engine as calculated by the signal from the camshaft position (CMP) sensor, shown in RPM

Cold Start Up

--

Varies

This parameter displays whether the engine meets the conditions for a cold startup during the present ignition cycle. The scan tool displays Yes when the conditions for a cold startup are met during this ignition cycle. The scan tool displays No when the conditions for a cold startup are not met during the present ignition cycle. Conditions for a cold startup require the coolant temperature and the intake air temperature to be below a predetermined temperature and within a certain range of each other. These conditions must occur after the engine was warmed up to a specific temperature during the previous ignition cycle.

Control Module Voltage Signal

--

B+

This parameter displays the state of the ignition system voltage available at the control module.

CPP Learn Status

--

Learned

This parameter displays the current state of the clutch pedal as determined by the control module.

CPP Learned Apply Position

--

Volts

This parameter displays the position learned for the clutch pedal position sensor when the clutch pedal is fully applied during the associated learn procedure.

CPP Learned Release Position

--

Volts

This parameter displays the position learned for the clutch pedal position sensor when the clutch pedal is released.

CPP Sensor

--

%

This parameter displays the displacement of the clutch pedal (corrected and normalized based upon its learned released and fully applied positions), where 0 % corresponds to the clutch pedal being released and 100% corresponds to the clutch pedal being fully applied.

CPP Sensor

--

Volts

This parameter displays the clutch pedal position sensor analog input as a percentage of its reference voltage.

Crank Request Signal

--

No

This parameter displays whether the ignition switch has been cycled to the crank position requesting the control module to activate the starter relay.

Cruise Cancel Switch

--

Inactive

This parameter displays the status of the cruise control cancel switch as determined by the control module. The scan tool will display Active when the cruise control cancel switch is on. The scan tool will display Inactive when the cruise control cancel switch is off.

Cruise Control Active

--

Inactive/No

This parameter displays the status of the cruise control system as determined by the control module.

Cruise Disengage 1-8 History

Cruise Control ON

Reason for Cruise Disengagement

The parameter displays the last 8 cruise control disengages in order from 1 to 8, with 8 being the most recent.

Cruise Inhibit Reason

Cruise Control ON

Varies

The parameter displays the reason why the cruise control system is inhibited.

Cruise ON/OFF Switch

Cruise Control ON

On

This parameter displays the state of the ON/OFF switch input to the control module.

Cruise Resume/Accel. Switch

--

Inactive

This parameter displays the state of the Resume/Accel switch input to the control module from the cruise control system.

Cruise Set/Coast Switch

--

Inactive

This parameter displays the state of the Set/Coast switch input to the control module from the cruise control system.

Cycles of Misfire Data

--

Incrementing 0-100

This parameter displays the number of cylinder firing events recorded by the control module

Cyl. 1-4 Injector Ckt Open Test Status

--

OK

This parameter displays the state of the injector control circuit. The scan tool displays OK , Fault, or Not Run. OK indicates that no circuit faults are detected during the current test.

Cyl. 1-4 Injector Ckt Short Gnd Test Status

--

OK

This parameter displays the state of the injector control circuit. The scan tool displays OK , Fault, or Not Run. OK indicates that no circuit faults are detected during the current test.

Cyl. 1-4 Injector Ckt Short Volts Test Status

--

OK

This parameter displays the state of the injector control circuit. The scan tool displays OK , Fault, or Not Run. OK indicates that no circuit faults are detected during the current test.

Cylinder 1-4 IC Ckt Open Test Status

--

OK/Not Run

This parameter displays the state of the Ignition control circuit. The scan tool displays OK , Fault, or Not Run. OK indicates that no circuit faults are detected during the current test.

Cyl. 1-4 IC Ckt Short Gnd Test Status

--

OK/Not Run

This parameter displays the state of the Ignition control circuit. The scan tool displays OK , Fault, or Not Run. OK indicates that no circuit faults are detected during the current test.

Cyl. 1-4 IC Ckt Short Volts Test Status

--

OK/Not Run

This parameter displays the state of the Ignition control circuit. The scan tool displays OK , Fault, or Not Run. OK indicates that no circuit faults are detected during the current test.

Decel Fuel Cut Off

--

Inactive

This parameter displays the status of the operating mode of the control module used to turn off the fuel injectors during certain deceleration conditions.

Desired ECT

--

Varies

This parameter displays the desired engine coolant temperature in degrees.

Desired Exh. CMP

--

3-7°

This parameter displays the desired exhaust camshaft angle as commanded by the control module.

Desired Idle Speed

--

600-950 RPM

This parameter displays the desired engine idle speed as commanded by the control module.

Desired Int. CMP

--

11-15°

This parameter displays the desired intake camshaft angle as commanded by the control module.

Distance Since DTC Cleared

--

Varies

This parameter displays the mileage that has elapsed since the DTC cleared.

Distance Since First Failure

--

Varies

This parameter displays the distance accumulated when the emission diagnostic trouble code first failed.

Distance Since Last Failure

--

Varies

This parameter displays the distance accumulated when the emission diagnostic trouble code last failed.

EC Ign. Relay Ckt Open Test Status

--

Not Run

This parameter displays the state of the EC Ignition Relay control circuit. The scan tool displays OK , Fault, or Not Run. OK indicates that no circuit faults are detected during the current test.

EC Ign. Relay Ckt Short Gnd Test Status

--

Not Run

This parameter displays the state of the EC Ignition Relay control circuit. The scan tool displays OK , Fault, or Not Run. OK indicates that no circuit faults are detected during the current test.

EC Ign. Relay Ckt Short Volts Test Status

--

OK

This parameter displays the state of the EC Ignition Relay control circuit. The scan tool displays OK , Fault, or Not Run. OK indicates that no circuit faults are detected during the current test.

EC Ignition Relay Command

--

ON

This parameter displays the commanded state of the EC Ignition relay control circuit. The scan tool will display ON or OFF. ON indicates the EC ignition relay control circuit is being grounded by the control module, allowing voltage to other control module circuits and systems. OFF indicates the EC ignition relay is not being commanded ON by the control module.

EC Ignition Relay Feedback Signal

--

Battery Voltage

This parameter displays the voltage available at the EC ignition relay pin of the control module.

ECM Authentication Status

--

Valid

This parameter indicates the result of the comparison between the last received immobilizer system response and the expected response calculated by the ECM.

ECM Challenge Status

--

Invalid

This parameter shows the immobilizer system status of the ECM challenge. This indicates whether the currently calculated ECM challenge is valid.

ECM Response Source

--

Normal

The parameter indicates the source used to calculate the ECM response. The sources include Normal Start, Remote Vehicle Start, PTO Remote Start.

ECT Sensor

--

-39 to +140°C (-38 to +284°F)

This parameter displays the temperature of the engine coolant based on input to the control module from the engine coolant temperature (ECT) sensor.

ECT/IAT Sen. Temp at Last ECT/RCT Fault Detected

--

Agree

This parameter displays that the temperature values of the ECT and IAT sensors did not agree at the time of the most recent failure of the ECT/RCT performance diagnostic.

Eng Clnt Therm Htr Ckt Open Test Status

--

OK

This parameter displays the status of the control circuit for the engine coolant thermostat heater. The scan tool will display OK , Fault or Not Run. OK indicates that no circuit faults are detected during the current test.

Eng Clnt Therm Htr Ckt Short Gnd Test Status

--

OK

This parameter displays the status of the control circuit for the engine coolant thermostat heater. The scan tool will display OK , Fault or Not Run. OK indicates that no circuit faults are detected during the current test.

Eng Clnt Therm Htr Ckt Short Volts Test Status

--

OK

This parameter displays the status of the control circuit for the engine coolant thermostat heater. The scan tool will display OK , Fault or Not Run. OK indicates that no circuit faults are detected during the current test.

Eng Clnt Therm Htr Command

--

0-100%

This parameter displays the commanded duty cycle for the engine coolant thermostat.

Engine Load

Engine Idling

25-40%

This parameter displays the calculated engine load in percent based on inputs to the control module from various engine sensors.

Engine speed at 2,500 RPM

25-40%

Engine Off Time

Ignition Switch in the OFF Position

Varies

This parameter displays the amount of time that has elapsed since the engine was last cycled OFF. The scan tool displays the time in hours, minutes, and seconds.

Engine Oil Pressure Switch

--

OK

This parameter displays the state of the EOP as determined by the control module. The control module monitors the EOP switch to determine if the EOP is sufficient. The scan tool displays Low when the EOP is below a predetermined value.

Engine Oil Temperature Calculated

--

Varies

This parameter displays the temperature of the engine oil as calculated by the control module using various sensor inputs. The engine oil temperature calculated has a range of values indicating a low value when the oil temperature is low to a high value when the oil temperature is high.

Engine Run Time

Engine Operating

Varies

This parameter displays the time elapsed since the engine was started. The scan tool will display the time in hours, minutes and seconds. The engine run time will reset to zero when the engine stops running.

Engine Speed

Engine Cranking

Greater than 60 RPM

This parameter displays the speed of the engine crankshaft rotation from information received from the crankshaft position (CKP) sensor.

Engine Idling

Approximately 650-950 RPM

EVAP Fault History

--

No Fault

This parameter displays the result of the evaporative emission (EVAP) system diagnostic as determined by the control module. The scan tool will display the following:

    • No Fault
    • Excess Vacuum
    • Purge Valve Leak
    • Small Leak
    • Weak Vacuum
    • No Test Result

EVAP Monitor Complete This Ignition

--

Yes/No

This parameter displays the diagnostic monitor completion status during the current driving/monitoring cycle

EVAP Monitor Enabled This Ignition

--

Yes/No

This parameter displays the diagnostic monitor enable status during the current driving/monitoring cycle.

EVAP Purge Sol Ckt Open Test Status

--

OK

This parameter displays the status of the evaporative emission (EVAP) purge solenoid control circuit. The scan tool displays OK , Fault, or Not Run. OK indicates that no circuit faults are detected during the current test.

EVAP Purge Sol Ckt Short Gnd Test Status

--

OK

This parameter displays the status of the evaporative emission (EVAP) purge solenoid control circuit. The scan tool displays OK , Fault, or Not Run. OK indicates that no circuit faults are detected during the current test.

EVAP Purge Sol Ckt Short Volts Test Status

--

OK

This parameter displays the status of the evaporative emission (EVAP) purge solenoid control circuit. The scan tool displays OK , Fault, or Not Run. OK indicates that no circuit faults are detected during the current test.

EVAP Purge Solenoid Command

--

10-20%

This parameter displays the on-time or duty cycle of the EVAP canister purge solenoid commanded by the control module. Zero percent indicates no purge. One hundred percent indicates full purge.

EVAP Vent Sol Ckt Open Test Status

--

OK

This parameter displays the status of the EVAP vent solenoid control circuit. The scan tool displays OK , Fault, or Not Run. OK indicates that no circuit faults are detected during the current test.

EVAP Vent Sol Ckt Short Gnd Test Status

--

OK

This parameter displays the status of the EVAP vent solenoid control circuit. The scan tool displays OK , Fault, or Not Run. OK indicates that no circuit faults are detected during the current test.

EVAP Vent Sol Ckt Short Volts Test Status

--

Not Run

This parameter displays the status of the EVAP vent solenoid control circuit. The scan tool displays OK , Fault, or Not Run. OK indicates that no circuit faults are detected during the current test.

EVAP Vent Solenoid Command

--

Venting

This parameter displays the state of the EVAP vent solenoid as commanded by the control module.

Exh CMP Sol Ckt Open Test Status

--

OK

This parameter displays the status of the exhaust camshaft actuator solenoid control circuit. The scan tool displays OK , Fault, or Not Run. OK indicates that no circuit faults are detected during the current test.

Exh CMP Sol Ckt Short Gnd Test Status

--

OK

This parameter displays the status of the exhaust camshaft actuator solenoid control circuit. The scan tool displays OK , Fault, or Not Run. OK indicates that no circuit faults are detected during the current test.

Exh CMP Sol Ckt Short Volts Test Status

--

OK

This parameter displays the status of the exhaust camshaft actuator solenoid control circuit. The scan tool displays OK , Fault, or Not Run. OK indicates that no circuit faults are detected during the current test.

Exh. CMP Active Counter

--

Varies in counts

This parameter displays an incrementing counter when the control module receives a signal from the exhaust camshaft position (CMP) sensor.

Exh. CMP Angle

--

2-8°

This parameter displays the retard position of the camshaft in degrees of camshaft rotation from the parked position. Zero indicates the camshaft is in the parked position.

Exh. CMP Command

--

45-75%

This parameter displays the commanded duty cycle for the exhaust camshaft as commanded by the control module.

Exh. CMP Variance

--

This parameter indicates the difference between the actual camshaft angle and the desired camshaft angle.

Fail Counter

--

Counts

This parameter displays the number of times a DTC failed

FC Relay 1 Ckt Open Test Status

--

OK/Not Run

This parameter displays the status of the fan relay control circuit. The scan tool displays OK , Fault, or Not Run. OK indicates that no circuit faults are detected during the current test.

FC Relay 1 Ckt Short Gnd Test Status

--

OK/Not Run

This parameter displays the status of the fan relay control circuit. The scan tool displays OK , Fault, or Not Run. OK indicates that no circuit faults are detected during the current test.

FC Relay 1 Ckt Short Volts Test Status

--

OK/Not Run

This parameter displays the status of the fan relay control circuit. The scan tool displays OK , Fault, or Not Run. OK indicates that no circuit faults are detected during the current test.

FC Relay 1 Command

--

Varies

This parameter displays the commanded state of the cooling fan relay 1 control circuit. The cooling fan relay 1 should be ON when the scan tool indicates the FC relay 1 command is ON. The cooling fan relay 1 should be OFF when the scan tool indicates the FC Relay 1 Command is OFF

FC Relay 2 Ckt Open Test Status

--

OK/Not Run

This parameter displays the state of the fan relay control circuit. The parameter displays Fault if the fan relay control circuit is open.

FC Relay 2 Ckt Short Gnd Test Status

--

OK/Not Run

This parameter displays the status of the fan relay control circuit. The scan tool displays OK , Fault, or Not Run. OK indicates that no circuit faults are detected during the current test.

FC Relay 2 Ckt Short Volts Test Status

--

OK/Not Run

This parameter displays the status of the fan relay control circuit. The scan tool displays OK , Fault, or Not Run. OK indicates that no circuit faults are detected during the current test.

FC Relay 2 Command

--

Varies

This parameter displays the commanded state of the cooling fan relay 2 control circuit. The cooling fan relay 2 should be ON when the scan tool indicates the FC Relay 2 command is ON. The cooling fan relay 2 should be OFF when the scan tool indicates the FC Relay 2 command is OFF.

Fuel Level Sensor

--

Varies

This parameter displays the voltage from the sensor used to monitor the fuel level inside the fuel tank.

Fuel Pump Relay Ckt Open Test Status

--

Not Run

This parameter displays the status of the fuel pump relay control circuit. The scan tool displays OK , Fault, or Not Run. OK indicates that no circuit faults are detected during the current test.

Fuel Pump Relay Ckt Short Gnd Test Status

--

OK

This parameter displays the status of the fuel pump relay control circuit. The scan tool displays OK , Fault, or Not Run. OK indicates that no circuit faults are detected during the current test.

Fuel Pump Relay Ckt Short Volts Test Status

--

Not Run

This parameter displays the status of the fuel pump relay control circuit. The scan tool displays OK , Fault, or Not Run. OK indicates that no circuit faults are detected during the current test.

Fuel Pump Relay Command

Ignition ON, engine OFF

Fuel pump on for 2 seconds

This parameter displays the control modules commanded state of the fuel pump relay control circuit.

Engine idling

On

Fuel Tank Level Remaining

--

Varies

This parameter displays the amount of fuel remaining in the fuel tank as measured in liters/gallons. The control module determines the amount of fuel remaining in the tank by using information from the fuel level sensor. The scan tool will display a higher value with a full fuel tank, and a lower value with an empty fuel tank.

Fuel Tank Level Remaining

--

Varies

This parameter displays the amount of fuel remaining in the fuel tank as measured in percentage. The control module determines the amount of fuel remaining in the tank by using information from the fuel level sensors. The scan tool will display a higher value with a full fuel tank, and a lower value with an empty fuel tank.

Fuel Tank Pressure Sensor

--

0.00 inch H2O

This parameter displays the pressure/vacuum inside the fuel tank. A negative value indicates a vacuum, while a positive value indicates a pressure.

Fuel Tank Pressure Sensor

--

1.3-1.7 Volts

This parameter displays the voltage signal received by the control module from the fuel tank pressure (FTP) sensor.

Fuel Tank Rated Capacity

--

44.9 L (11.9 Gal)

This parameter displays the rated maximum quantity of fuel the fuel tank will hold. This is calibrated in the control module to match the vehicle.

Fuel Trim Cell

--

6

This parameter displays what fuel trim cell that is currently active.

Fuel Trim Learn

--

Enabled

This parameter displays Enabled when conditions are appropriate for enabling long term fuel trim corrections. This indicates that the long term fuel trim is adapting continuing amounts of short term fuel trim. If the scan tool displays Disabled, then long term fuel trim will not respond to changes in short term fuel trim.

Fuel Trim System Test State

--

Monitoring

This parameter indicates the status of the Fuel Trim System Test. The scan tool will display Disabled, Enabled, Monitoring, or Run Purge Test.

Fuel Volatility

--

Varies

This parameter indicates the rate the fuel can be vaporized in the cylinder as calculated by the control module. The scan tool displays Low, Moderate, or High. The scan tool will display HIGH when the fuel volatility is high. The scan tool will display LOW when the fuel volatility is low.

GEN F-Terminal Signal

--

40-70 %

This parameter indicates the generator field duty cycle as commanded by the voltage regulator or control module. The scan tool will display a higher value for a higher commanded generator output, and a lower value for a lower commanded generator output.

GEN L-Terminal Ckt Open Test Status

--

Not Run

This parameter displays the status of the Gen-L Terminal circuit. The scan tool displays OK , Fault, or Not Run. OK indicates that no circuit faults are detected during the current test.

GEN L-Terminal Ckt Short Gnd Test Status

--

OK

This parameter displays the status of the Gen-L Terminal circuit. The scan tool displays OK , Fault, or Not Run. OK indicates that no circuit faults are detected during the current test.

GEN L-Terminal Ckt Short Volts Test Status

--

Not Run

This parameter displays the status of the Gen-L Terminal circuit. The scan tool displays OK , Fault, or Not Run. OK indicates that no circuit faults are detected during the current test.

GEN L-Terminal Command

--

0-100%

This parameter displays the control modules commanded state of the voltage regulator on the generator.

GEN L-Terminal Signal Command

--

ON

This parameter displays the commanded state of the generator L-terminal output.

HO2S 1 or HO2S 2

Ignition ON, Engine OFF

1275 mV

This parameter indicates the heated oxygen sensor (HO2S) sensor 1 or 2, output voltage as measured by the control module. The scan tool will display a higher value during a rich condition, and a lower value during a lean condition.

Engine Operating

Varies

HO2S 1 or HO2S 2 Heater

--

0.42-0.62 Amps

This parameter displays the amperage of the HO2S heater commanded by the control module.

HO2S 1 or HO2S 2 Heater Command

--

ON

This parameter displays the commanded state of the HO2S  1 or HO2S 2 heater circuit by the control module. The scan tool will display ON when the heater is commanded ON. The scan tool will display OFF when the heater is commanded OFF.

HO2S  1 or HO2S 2 Heater Command

--

0-99%

This parameter displays the commanded state of the Bank 1 Sensor 2 heater by the control module. The scan tool will display a higher value as the heater command is increased, and a lower value if the heater is not commanded ON.

HO2S  1 or HO2S 2 Htr Ckt Open Test Status

--

OK

This parameter displays the status of the control circuit for the HO2S  1 or HO2S 2. The scan tool displays OK , Fault, or Not Run. OK indicates that no circuit faults are detected during the current test.

HO2S  1 or HO2S 2 Htr Ckt Short Gnd Test Status

--

OK

This parameter displays the status of the control circuit for the HO2S  1 or HO2S 2. The scan tool displays OK , Fault, or Not Run. OK indicates that no circuit faults are detected during the current test.

HO2S  1 or HO2S 2 Htr Ckt Short Volts Test Status

--

OK

This parameter displays the status of the control circuit for the HO2S  1 or HO2S 2. The scan tool displays OK , Fault, or Not Run. OK indicates that no circuit faults are detected during the current test.

HO2S Heater Monitor Complete This Ignition

--

Yes/No

This parameter displays the diagnostic monitor completion status during the current driving/monitoring cycle.

HO2S Heater Monitor Enabled This Ignition

--

Yes/No

This parameter displays the diagnostic monitor enable status during the current driving/monitoring cycle.

HO2S/O2S Monitor Complete This Ignition

--

Yes/No

This parameter displays the diagnostic monitor completion status during the current driving/monitoring cycle.

HO2S/O2S Monitor Enabled This Ignition

--

Yes/No

This parameter displays the diagnostic monitor enable status during the current driving/monitoring cycle.

Hot Open Loop

--

Inactive

This parameter displays the status of the fuel delivery system. The scan tool will display Active if the fuel system is running in open loop due to a temperature condition. The scan tool will display Inactive if the fuel system is operating normally.

IAT Sensor

--

-39 to +140°C ( -38 to +284°F)

This parameter displays the temperature of the air entering the air induction system based on input to the control module from the intake air temperature (IAT) sensor.

Ignition Accessory Signal

--

ON

This parameter displays the state of the ignition 0 input to the control module from the ignition switch.

Inj. 1-4 Disabled Due to Misfire

--

No

This parameter displays the status of the fuel injector driver by the control module. The scan tool will display YES if the fuel injector is being disabled due to a misfire detection. The scan tool will display NO if the fuel injector is not being disabled by the control module due to a misfire.

Injector PWM

--

2-3 ms

This parameter displays the average pulse width of the fuel injectors as determined by the control module.

Int CMP Sol Ckt Open Test Status

--

OK

This parameter displays the status of the control circuit for the Int CMP solenoid. The scan tool displays OK , Fault, or Not Run. OK indicates that no circuit faults are detected during the current test.

Int CMP Sol Ckt Short Gnd Test Status

--

OK

This parameter displays the status of the control circuit for the Int CMP solenoid. The scan tool displays OK , Fault, or Not Run. OK indicates that no circuit faults are detected during the current test.

Int CMP Sol Ckt Short Volts Test Status

--

OK

This parameter displays the status of the control circuit for the Int CMP solenoid. The scan tool displays OK , Fault, or Not Run. OK indicates that no circuit faults are detected during the current test.

Int. CMP Active Counter

--

Varies in counts

This parameter displays an incrementing counter when the control module receives a signal from the intake camshaft position (CMP) sensor.

Int. CMP Angle

--

8-18°

This parameter displays the advance position of the camshaft in degrees of camshaft rotation from the parked position. Zero indicates the camshaft is in the parked position.

Int. CMP Command

--

45-75%

This parameter displays the commanded duty cycle for the intake camshaft as commanded by the control module.

Int. CMP Variance

--

0 Degrees

This parameter indicates the difference between the actual camshaft angle and the desired camshaft angle.

Intake Manifold Pressure

--

32-53 kPa (4.6-7.6 psi)

This parameter displays the pressure difference between the MAP and the barometric pressure (BARO) as calculated by the control module.

Knock Detected Cyl. 1-4

--

NO

This parameter displays the status of each cylinder for knock detection by the control module. The scan tool will display YES if a knock condition has been detected related to that cylinder combustion event. The scan tool will display NO if there is no knock condition detected related to that cylinder combustion event.

Knock Retard

--

This parameter displays the amount of spark advance the control module removes from the ignition control (IC) spark advance in response to the signal from the knock sensors.

Long Term FT

--

-5 to +5 %

This parameter displays the commanded Long Term Fuel Trim correction by the control module.

Loop Status

--

Closed Loop

This parameter displays the state of the fuel control system as commanded by the control module. Closed Loop operation indicates that the control module is controlling the fuel delivery based off the oxygen sensors input signal. In Open Loop operation the control module ignores the oxygen sensor input signal and bases the amount of fuel to be delivered on other sensor inputs.

LT FT Test Avg.

--

0.98

This parameter displays the long term closed loop fuel correction. This value is compared to predetermined thresholds to determine if the fuel trim diagnostic is passing or failing.

LT FT Test Avg. w/o Purge

--

0.98 %

This parameter displays the non purge long term closed loop fuel correction This value is compared to predetermined thresholds to determine if the fuel trim diagnostic is passing, failing, or indeterminate during normal purge-off operation as well as during the intrusive excess purge vapor test.

MAF Performance Test

--

OK

This parameter displays the status of the mass air flow (MAF) performance test by the control module. The scan tool will display OK if no condition is detected. The scan tool will display Fault if the control module detects a condition during the test.

MAF Sensor

Engine Idling

1.7-3.7 g/s

This parameter indicates the quantity calculated by the control module based on a signal from the MAF sensor. The scan tool will display a high value at high engine speeds, and a low value at low engine speeds.

Engine speed at 2,500 RPM

5.5-7.5 g/s

MAF Sensor

--

1,700-2,100 Hz

This parameter indicates the frequency signal received from the MAF sensor by the control module. The scan tool will display a high value at high engine speeds, and a low value at low engine speeds.

MAP Performance Test 1

--

OK

This parameter displays the status of the MAP performance test 1 by the control module. The scan tool will display OK if no fault is found. The scan tool will display Fault if the control module detects a fault during the test.

MAP Performance Test 2

--

OK

This parameter displays the status of the MAP performance test 2 by the control module. The scan tool will display OK if no fault is found. The scan tool will display Fault if the control module detects a fault during the test.

MAP Sensor

--

26-52 kPa

This parameter displays the pressure from the MAP sensor to the control module

MAP Sensor

--

0.98-1.42 Volts

This parameter displays the signal voltage from the MAP sensor to the control module.

MIL Ckt Open Test Status

--

OK

This parameter displays the status of the control circuit for the malfunction indicator lamp control (MIL). The scan tool displays OK , Fault, or Not Run. OK indicates that no circuit faults are detected during the current test.

MIL Ckt Short Gnd Test Status

--

OK

This parameter displays the status of the control circuit for the malfunction indicator lamp control (MIL). The scan tool displays OK , Fault, or Not Run. OK indicates that no circuit faults are detected during the current test.

MIL Ckt Short Volts Test Status

--

Not Run

This parameter displays the status of the control circuit for the malfunction indicator lamp control (MIL). The scan tool displays OK , Fault, or Not Run. OK indicates that no circuit faults are detected during the current test.

MIL Command

--

Off

This parameter displays the commanded state of the malfunction indicator lamp (MIL) control circuit by the control module.

MIL Requested by DTC

--

No

This parameter indicates the reason the control module illuminated the MIL. The scan tool will display YES when the MIL is requested as a result of an A or B type DTC. The scan tool will display NO if the MIL is illuminated for another reason, such as transmission DTCs.

Misfire Current Cyl. 1-4

--

0 Counts

This parameter displays the number of misfires that have been detected during the last 200 cylinder firing events. The counters may normally display some activity, but the activity should be nearly equal for all of the cylinders, and in low numbers.

Misfire History Cyl. 1-4

--

0 Counts

The misfire history counters display the total level of misfire that has been detected on each cylinder. The misfire history counters will not update or show any activity until a misfire DTC P0300 has become active. The misfire history counters will update every 200 cylinder firing events.

Not Run Counter

--

Counts

This parameter displays the number of times a DTC does not run.

Pass Counter

--

Counts

This parameter displays the number of times a DTC passed.

Power Enrichment

--

Inactive

This parameter displays the status of the operating mode of the control module used to increase fuel delivery during certain acceleration conditions.

Radiator Clnt. Temp. Sensor

--

-39 to +140°C (-38 to +284°F)

This parameter displays the status of the radiator coolant. temperature Sensor.

RCT/IAT Sen. Temp at Last ECT/RCT Fault Detected

--

Agree

This parameter displays that the temperature values of the ECT and IAT sensors did not agree at the time of the most recent failure of the ECT/RCT performance diagnostic.

Reduced Engine Power

--

Inactive

This parameter displays the status of the operating mode of the control module used to reduce engine power to prevent catalytic converter or engine damage or due to a Throttle Actuator Control (TAC) system failure.

Reduced Engine Power History

--

OK

This parameter displays the last reason that ECM has Commanded Reduced Engine Power. The scan tool displays one of the following when Reduced Engine Power is commanded:

    • TAC DTC
    • FC DTC
    • ECT Overtemp
    • Eng Oil Overtemp

Reverse Switch

--

OFF

Manual Transmission Reverse Switch On indicates that the reverse switch hard wire input to the ECM is active.

Short Term FT

--

-5% to +5%

This parameter displays the short-term correction to the fuel delivery by the control module in response to oxygen sensor. If the oxygen sensor indicates a lean air/fuel mixture, the control module will add fuel increasing the short term fuel trim above 0. If the oxygen sensor indicates a rich air/fuel mixture, the control module will reduce fuel decreasing the short term fuel trim below 0.

Spark

--

-2 to +2°

This parameter displays the amount of spark advance the control module is commanding. The control module determines the desired advance.

ST FT Test Avg.

--

0.99 %

This parameter displays the short term closed loop fuel correction. This value is compared to predetermined thresholds to determine if the fuel trim diagnostic is passing or failing.

Start Up ECT

--

-39° to +140°C

(-38° to +284°F)

This parameter displays the temperature of the engine coolant on start up based on input to the control module from the ECT sensor.

Start Up IAT

--

-39° to +140°C

(-38° to +284°F)

This parameter displays the temperature of the intake air at start in the air induction system based on input to the control module from the IAT sensor.

Starter Relay Ckt Open Test Status

--

OK

This parameter displays the status of the control circuit for the starter relay. The scan tool displays OK , Fault, or Not Run. OK indicates that no circuit faults are detected during the current test.

Starter Relay Ckt Short Gnd Test Status

--

Not Run

This parameter displays the status of the control circuit for the starter relay. The scan tool displays OK , Fault, or Not Run. OK indicates that no circuit faults are detected during the current test.

Starter Relay Ckt Short Volts Test Status

--

OK

This parameter displays the status of the control circuit for the starter relay. The scan tool displays OK , Fault, or Not Run. OK indicates that no circuit faults are detected during the current test.

Starter Relay Command

--

OFF

The scan tool displays ON/OFF. The scan tool displays OFF until the ignition is placed into the CRANK position.

TAC Forced Engine Shutdown

--

NO

This parameter indicates the status of TAC control by the control module. The scan tool will display YES if the engine has been shut down due to a throttle control fault. The scan tool will display NO if the engine has not been shut down by a throttle control fault.

TAC Motor

--

Enabled

This parameter indicates the status of the TAC motor driver by the ECM. The scan tool will display Enabled if TAC motor operation is allowed. The scan tool will display disabled if the TAC motor is disabled.

TAC Motor Command

--

Varies

This parameter displays the percentage of the commanded state of the TAC motor by the control module.

TB Idle Airflow Compensation

--

Varies

This parameter displays the amount of airflow compensation in response to engine intake air flow restrictions. For example, throttle plate coking.

TCC/Cruise Brake Pedal Switch

--

Released

This parameter displays that the state of the redundant discrete brake switch input to the controller indicates that the brake is applied.

TCS Torque Delivered Signal

--

0-3 %

This parameter displays the estimated engine torque delivered by the powertrain, as a percentage of maximum engine torque, that is provided to the ABS/TCS module via the delivered torque PWM output from the ECM.

TCS Torque Request Signal

--

0 ft-lbs

This parameter displays the estimated engine torque delivered by the powertrain, as a percentage of maximum engine torque, that is provided to the ABS/TCS module via the delivered torque PWM output from the ECM.

TCS Torque Request Signal

--

0 %

This parameter displays the torque delivered from the engine to the transmission as calculated by the control module. The scan tool will display a higher value for higher torque, and a lower value for lower torque.

TFT Sensor

--

-39° to +140°C

(-38° to +284°F)

This value represents the input signal of the transmission fluid temperature sensor.

Torque Delivered Signal

--

1-5 ft-lbs

This parameter displays the torque delivered from the engine to the transmission as calculated by the control module. The scan tool will display a higher value for higher torque, and a lower value for lower torque.

Torque Management Spark Retard

--

15-25°

This parameter displays how much the ignition spark timing is being retarded to control torque by the control module. The scan tool will display a higher value under extreme torque control conditions such as spinning wheels. The scan tool will display a lower value under low torque control conditions such as light driving.

Total Knock Retard

--

This parameter displays how much ignition spark timing is being retarded due to all control systems monitored by the control module. The scan tool will display a high value during extreme conditions such as high temperatures and antilock braking. The scan tool will display a lower value during lighter driving conditions.

Total Misfire

--

0 Counts

This parameter displays the total number of cylinder firing events that the control module detected as misfires for the last 200 crankshaft revolution sample period.

TP Desired Angle

--

2-6 %

This parameter displays the desired TP angle commanded by the control module.

TP Indicated Angle

--

2-6 %

This parameter displays the actual TP angle indicated by the control module using information from the two TP sensors.

TP Performance Test

--

OK

This parameter displays the status of the TP performance test by the control module. The scan tool will display OK if no fault is found. The scan tool will display Fault if the control module detects a fault during the test.

TP Sensor 1

Accelerator pedal not actuated

4.14-4.34 V

This parameter displays the voltage signal sent to the control module from TP sensor 1 of the throttle assembly. The TP sensor 1 is a range of values indicating a high voltage when the throttle is closed to a low voltage when the throttle plate is fully open.

Accelerator pedal fully actuated

3.50-3.37 V

TP Sensor 1 Indicated Position

--

2-6 %

This parameter displays the angle of the throttle position (TP) sensor 1 as calculated by the control module using the signal from the TP sensor 1. The TP sensor 1 is a range of values indicating a low percentage when the throttle is closed to a high percentage when the throttle is fully open.

TP Sensor 1 Learned Minimum

--

0.51-0.71 V

This parameter displays the learned minimum voltage for TP sensor 1 as determined by the control module this ignition cycle.

TP Sensor 2

Accelerator pedal not actuated

0.68-0.88 V

This parameter displays the voltage signal sent to the control module from TP sensor 2 of the throttle assembly. The TP sensor 2 is a range of values indicating a low voltage when the throttle is closed to a high voltage when the throttle plate is fully open.

Accelerator pedal fully actuated

1.35-1.55 V

TP Sensor 2 Indicated Position

--

2-6 %

This parameter displays the angle of the TP sensor 2 as calculated by the control module using the signal from the TP sensor 2. The TP sensor 2 is a range of values indicating a low percentage when the throttle is closed to a high percentage when the throttle is fully open.

TP Sensor 2 Learned Minimum

--

0.55-0.75 V

This parameter displays the learned minimum voltage for TP sensor 2 as determined by the control module this ignition cycle.

TP Sensors 1 and 2

--

Agree

This parameter displays the results of a control module test that compares the signals from the TP sensors 1 and 2. The scan tool will display Agree or Disagree. Agree indicates that TP sensor 1 and TP sensor 2 voltages correspond to the same throttle position. Disagree indicates that TP sensor 1 and TP sensor 2 voltages correspond to different throttle positions.

TWC Mon. Test Count

--

0 Counts

This parameter displays the number of iterations of the catalyst monitor diagnostic test that have been performed since a code clear for bank 1 (used to determine if a sufficient number of tests have run to report a passing condition).

TWC Mon. Off Idle Test Conditions Met

--

Yes/No

This parameter displays the status of the catalyst monitor diagnostic. Off Idle Conditions Met indicates if the off idle conditions for the catalyst monitor diagnostic have been met. Once the Off Idle Conditions are met the vehicle can return to idle and allow the catalyst monitor diagnostic test to run.

TWC Monitor Test Result

--

Varies

This parameter displays the status of the catalyst monitor diagnostic.

TWC Monitor Test State

--

Varies

This parameter displays when the catalyst monitor diagnostic is actively running a test. This condition will only be true when the vehicle is at idle.

Upshift Indicator Command

--

Off

This parameter displays that the transmission upshift indication is being requested on over serial communication in order to recommend that the driver shift up to a higher gear to improve fuel economy.

Vehicle Speed Sensor

--

0 Km/h

0 mph

This parameter displays the speed of the vehicle as calculated by the transmission control module (TCM) from information received from the vehicle speed sensor (VSS).

VTD Auto. Learn Counter

--

Counts

The scan tool displays the count value when using the 30 minute reprogramming procedure. Three 10 minute cycles, or three counts, are required to complete the 30 minute auto learn reprogramming procedure.

VTD Auto. Learn Timer

--

HH:MM:SS

This parameter displays that either the auto learn timer (used in the auto learn procedure to enable VTD password learning) or the seed and key timer (used in the seed and key procedure to enable VTD password learning) is active.

VTD Password Learn Enabled

--

Yes

The scan tool will display Yes when a valid theft password has been learned.

VTD Security Code Accepted

--

No

This parameter displays that the received immobilizer system security code is correct.

VTD Security Code Lockout

--

Inactive

This parameter displays Active or Inactive. Security Code Lockout Active indicates that the security code has not passed and lockout is active.

VTD Security Code Programmed

--

Varies

This parameter indicates if the immobilizer system security code has been programmed.

VTD Security Info. Programmed

--

Varies

This parameter displays if the immobilizer secret information, e.g. powertrain pre-release password, powertrain secret key, has been programmed.

VTD System Status

--

Varies

This parameter displays the current state of the immobilizer algorithm. The states include the following: Standby, Disabled at Startup, Disabled Due to No Response, Disabled Due to Negative Response, Disabled Due to Incorrect Response, Post Release, Pre-Release, Released.

Warm-ups Since DTC Cleared

--

Varies

This parameter displays the number of warm-ups since the DTC was cleared.

Warm-ups w/o Emission Faults

--

Varies

This parameter displays the number of warm up cycles that have occurred without an emission fault present. The scan tool will display a 0 if a fault has occurred. The scan tool will display a higher count if a number of warm up cycles have occurred without an emission fault.

Warm-ups w/o Non-Emission Faults

--

Varies

This parameter displays the number of warm up cycles that have occurred without a non-emission fault present. The scan tool will display a 0 if a fault has occurred. The scan tool will display a higher count if a number of warm up cycles have occurred without a non-emission fault.

Wide Open Throttle

--

NO

This parameter displays the throttle status commanded by the control module. The scan tool will display YES is the vehicle throttle is commanded to wide open. The scan tool will display NO if the vehicle throttle is commanded to an amount less than 100%.

Engine Control Module (ECM) Scan Tool Output Controls

Output Control

Description

A/C Relay

This function activates the A/C compressor relay. The normal commanded state of the A/C relay is None. The A/C compressor will turn ON/OFF when commanded ON/OFF. The system remains in the commanded state until cancelled by the scan tool. The scan tool initiates the test when the following conditions are met:

    • In the correct power mode
    • A/C high side pressure is in range
    • Engine speed is in range
    • Ignition voltage is in range
    • There are no A/C pressure sensor DTCs set.

Cylinder Power Balance

This function disables the selected fuel injector. The normal commanded state is None. The scan tool initiates the test when the following conditions are met:

    •  The engine is operating and the engine idle is stable.
    • The vehicle speed is 0 km/h (0 mph).
    • There are no vehicle speed sensor DTCs set.

If the fuel injector is disabled after 30 seconds, fuel injector control is not allowed again on the same fuel injector for 60 seconds.

Engine Controls Ignition Relay

This function controls the engine control (EC) ignition relay or main relay. The normal commanded state is None. When commanded ON or OFF, the engine control module (ECM) turns the relay ON or OFF. The system remains in the commanded state until cancelled by the scan tool. The scan tool initiates the test when the following conditions are met:

    • The ignition is ON with the engine OFF.
    • There are no CKP or VSS sensor DTCs set.
    • The vehicle speed is 0 km/h (0 mph).
    • In the correct power mode

Engine Coolant Thermostat Heater

This function controls the engine coolant thermostat heater. The normal commanded state is None. The system will increase or decrease the amount of thermostat opening by changing the duty cycle in 10 percent increments within a range of 0-100 percent.

Engine Speed Control

This function controls the idle speed override in 25 RPM, 100 RPM, and 500 RPM increments, from the base idle speed to 1,950 RPM. The scan tool initiates the test when the following conditions are met:

    • The vehicle speed is 0 km/h (0 mph)
    • There are no VSS sensor DTCs set
    • Transmission in Park or Neutral
    • No transmission range switch DTCs set

EVAP Purge Solenoid

This function controls the EVAP purge solenoid valve. The normal commanded state is None. The system will increase or decrease the amount of purge by changing the duty cycle of the purge valve in 10 percent increments within a range of 0-100 percent. The scan tool initiates the test when the following conditions are met:

    • The vacuum level in the EVAP purge system is within range
    • There are no EVAP DTCs set
    • The EVAP system test is not in progress
        In the correct Power Mode

EVAP Purge/Seal

This function simultaneously activates the purge solenoid in 10 percent increments from 0 to 100 percent and the vent solenoid. The device control will be aborted and inhibited if the FTP sensor exceeds about 24 mm Hg (12 in H2O). The scan tool initiates the test when the following conditions are met:

    • The vacuum level in the EVAP purge system is within range
    • There are no EVAP DTCs set
    • The EVAP system test is not in progress
        In the correct Power Mode

EVAP Test

Activates the on-board EVAP diagnostic test.

EVAP Vent Solenoid

This function controls the EVAP vent solenoid. The normal commanded state is None. When commanded ON, the vent valve switches to Not-venting. When commanded OFF, the vent valve switches to Venting. The scan tool initiates the test when the following conditions are met:

    • The vacuum level in the EVAP purge system is within range
    • There are no EVAP DTCs set
    • The EVAP system test is not in progress
        In the correct Power Mode

Exhaust CMP Actuator

This function controls the selected camshaft actuator solenoid. The normal commanded state is None. The system will increase or decrease the angle of the selected camshaft in 5 degree increments. The scan tool initiates the test when the following conditions are met:

    • The engine is operating.
    • The commanded camshaft position is not out of range.
    • There are no CKP or CMP sensor DTCs set.
    • Engine oil temperature is not out of range.
    • In the correct power mode

If the actuator is disabled after 30 seconds, the actuator control is not allowed again on the same actuator for 60 seconds.

Exh. CMP Actuator Sol.

This function controls the selected camshaft actuator solenoid. The normal commanded state is None. When commanded ON the solenoid is commanded to 100 percent. When commanded OFF the solenoid is commanded to 0 percent. The scan tool initiates the test when the following conditions are met:

    • The engine speed is 0 RPM.
    • In the correct power mode

If the actuator is disabled after 30 seconds, the actuator control is not allowed again on the same actuator for 60 seconds.

Fan Relay 1 & 2

This function controls the cooling fan relay 1 & 2. The normal commanded state of the fan relay is None. The scan tool initiates the test when the following conditions are met:

    • Engine coolant temperature is not out of range.
    • In the correct power mode

Fuel Injector Balance

This function enables the fuel injector in order to verify proper fuel injector flow. The ECM will pulse the selected injector when the following conditions are met:

    • All instruction on the scan tool completed
    • Fuel injector selected
    • Key ON, engine OFF

The selected fuel injector can only be flowed/pulsed once per ignition cycle.

Fuel Pump Relay

This function controls the fuel pump relay. The normal commanded state is None. When commanded ON/OFF, the ECM turns the fuel pump ON/OFF. The scan tool initiates the test when the following conditions are met:

    • The engine speed is 0 RPM.
    • In the correct power mode
    • The output control timer has not expired
    • The ignition voltage is within range

Fuel Trim Enable

This function enables or disables the ECM fuel trim learning. The normal commanded state is None.

Fuel Trim Reset

This function is used to reset the learned fuel trim values to their initial values.

GEN L-Terminal

This function is used to override the state of the generator L terminal output. The commanded states are ON and OFF. Selecting OFF commands the ECM to turn OFF the generator and stop generating an output voltage.

    • The engine is operating to turn OFF the component
    • The vehicle speed is 0 km/h (0 mph)
    • Transmission in Park or Neutral
    • In the correct power mode
    • The output control timer has not expired

HO2S Heater Learn

This function is used to trigger the reset of the learned resistances for the oxygen sensor heaters following a replacement. The learned resistances are reset to a calibration used to prevent overheating of the sensors until more accurate resistances may be learned following an extended engine OFF time.

HO2S Heater Sensor 1 & 2

This function controls the selected HO2S heater. The normal commanded state is None. Commanding the HO2S heater ON turns on the heater driver. The scan tool initiates the test when the following conditions are met:

    • The engine is operating
    • The exhaust temperature is within range
    • In the correct power mode
    • The HO2S heaters are not over temperature
    • The ignition voltage is not out of range while commanding the heaters ON

Idle Learn Reset

This function is used to reset the learned airflow adaptive values to the initial values. The scan tool initiates the test when the following conditions are met:

    • The vehicle speed is 0 km/h (0 mph).
    • In the correct power mode
    • The transmission is in Park or Neutral.
    • There are no throttle actuator control system DTCs set

Idle Spark

This function is used to disable the portion of the spark control algorithm that adjusts spark angle to correct the difference between commanded idle engine speed and actual idle engine speed.

Intake CMP Actuator

This function controls the selected camshaft actuator solenoid. The normal commanded state is None. The system will increase or decrease the angle of the selected camshaft in 5 degree increments. The scan tool initiates the test when the following conditions are met:

    • The engine is operating.
    • The commanded camshaft position is not out of range.
    • There are no CKP or CMP sensor DTCs set.
    • Engine oil temperature is not out of range.
    • In the correct power mode

If the actuator is disabled after 30 seconds, the actuator control is not allowed again on the same actuator for 60 seconds.

Int. CMP Actuator Sol.

This function controls the selected camshaft actuator solenoid. The normal commanded state is None. When commanded ON the solenoid is commanded to 100 percent. When commanded OFF the solenoid is commanded to 0 percent. The scan tool initiates the test when the following conditions are met:

    • The engine speed is 0 RPM.
    • In the correct power mode

If the actuator is disabled after 30 seconds, the actuator control is not allowed again on the same actuator for 60 seconds.

Loop Status

This device control is used to enable or disable closed loop fuel control.

Malfunction Indicator Lamp

This function controls the malfunction indicator lamp (MIL). The normal commanded state is None. When commanded ON/OFF, the ECM turns the malfunction indicator lamp (MIL) ON/OFF. This output can also be monitored on the scan tool data parameter MIL Command. The system remains in the commanded state until cancelled by the scan tool.

Misfire Graphic

This function is used to graph the accumulated misfires occurring in each cylinder. The scan tool allows for a reset of the misfire graph.

Oil Life Reset

This function is used to reset the engine oil life. The engine oil remaining life is determined from engine revolutions and the distance driven since the last oil change.

Spark Retard

This function is used to control the amount of spark retard. The normal commanded state is None. The system will increase or decrease the amount of spark retard by 1 degree increments within a range of 0-10 degrees maximum retard. The system remains in the commanded state until cancelled by the tool.

Starter Relay

This function is used to override the state of the Starter Relay output. Fuel and spark are disabled to prevent the engine from starting if the starter relay output is commanded ON. The scan tool initiates the test when the following conditions are met:

    • The engine speed is 0 RPM.
    • There are no CKP sensor DTCs set
    • The vehicle speed is 0 km/h (0 mph)
    • There are no VSS sensor DTCs set
    • There are no theft deterrent DTCs set
    • Transmission is in Park or Neutral
    • No transmission range switch DTCs set
    • There are no TAC system DTCs set
    • The ignition voltage is within range
    • In the correct power mode
    • Not enough time has elapsed since the last time the starter has been enabled with a scan tool

Throttle Position

This function controls the throttle valve in 10 percent increments. The scan tool initiates the test when the following conditions are met:

    • The engine speed is 0 RPM.
    • The vehicle speed is 0 km/h (0 mph).

The system remains in the commanded state until cancelled by the scan tool.