GM Service Manual Online
For 1990-2009 cars only

The Engine Scan Tool Data List contains all engine related parameters that are available on the scan tool. The list is arranged in alphabetical order. A given parameter may appear in any one of the data lists, and in some cases may appear more than once, or in more than one data list in order to group certain related parameters together.

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

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

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 normal running engine.

Important: A scan tool that displays faulty data should not be used. The scan tool problem 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. If all values are within the typical range described below, refer to Symptoms - Engine Controls for diagnosis.

The column labeled Data List indicates where a parameter can be located on the scan tool. Refer to the scan tool operating manual for the exact locations of the data lists. The following is a description of each term listed:

All: The Parameter is in all of the data lists indicated below.

Eng 1: Engine Data 1 List

Eng 2: Engine Data 2 List

EE: Enhanced Evaporative Emission (EVAP) Data

FF/FR: Freeze Frame/Failure Records

FT: Fuel Trim Data List

MF: Misfire Data List

TAC: Throttle Actuator Control (TAC) Data List

CC: Cruise Control Data List

HO2S Data: Heated Oxygen Sensor (HO2S) Data List

Scan Tool Parameter

Data List

Parameter Range/Units

Typical Data Values

Operating Conditions: Engine Idling/Radiator Hose Hot/Closed Throttle/Park or Neutral/Closed Loop/Accessories OFF

4WD Signal

Eng 2

Enabled/Disabled

Disabled

4WD Low Signal

Eng 2

Enabled/Disabled

Disabled

A/C Pressure Sensor

Eng 2

Volts

0.98 Volts/Varies

A/C Pressure Sensor

Eng 2

PSI

90 PSI/Varies

A/C Relay Command

Eng 1, 2, MF

On/Off

Off

A/C Request Signal

Eng 2

Yes/No

No

APP Average

TAC

0-100%

0%

APP Indicated Angle

Eng 1, Eng 2, EE, CC, FT, TAC, HO2S

Counts

0

APP Sensor 1

TAC

0-5.0 Volts

0.4-0.9 Volts

APP Sensor 2

TAC

5.0-0 Volts

4.5-4.1 Volts

APP Sensor 1

TAC

0-100%

0%

APP Sensor 2

TAC

0-100%

0%

APP Sensor 1 and 2

TAC

Agree/Disagree

Agree

BARO

Eng 1, EE, FT

kPa

50-104 kPa/ Varies w/Altitude

CMP Sensor-High to Low

Eng 2

Counts

Varies

CMP Sensor-Low to High

Eng 2

Counts

Varies

Clutch Pedal Switch

Eng 2

Released/Applied

Released

Coolant Level Switch

Eng 2

OK/Low

OK

Cruise Control Active

Eng 1, TAC, CC

Yes/No

No

Cruise Disengage 1 History

CC

Varies

Varies

Cruise Disengage 2 History

CC

Varies

Varies

Cruise Disengage 3 History

CC

Varies

Varies

Cruise Disengage 4 History

CC

Varies

Varies

Cruise Disengage 5 History

CC

Varies

Varies

Cruise Disengage 6 History

CC

Varies

Varies

Cruise Disengage 7 History

CC

Varies

Varies

Cruise Disengage 8 History

CC

Varies

Varies

Cruise Inhibit Signal Command

Eng 1

On/Off

On

Cruise On/Off Switch

CC, TAC

On/Off

Off

Cruise Release Brake Pedal Switch

CC

Released/Applied

Released

Cruise Resume/Accel Switch

CC, TAC

On/Off

Off

Cruise Set/Coast Switch

CC, TAC

On/Off

Off

Current Gear

Eng 1, 2, FT

0-4

1

Cycles of Misfire Data

MF

0-100 Counts

Varies

Decel Fuel Cutoff

HO2S

Active/Inactive

Inactive

Desired IAC Airflow

Eng 1

0-64 g/s

Varies

Desired Idle Speed

Eng 1, Eng 2, TAC, EE

RPM

PCM Controlled

DTC Set This Ignition

Eng 1, 2, CC, EE, FT, HO2S

Yes/No

No

ECT Sensor

Eng 1, Eng 2, EE, FT, MF, HO2S

-39 to +140°C (-38 to +284°F)

88-105°C (190-221°F)

Engine Load

All

0-100%

1-4% @ Idle

7-9% @ 2500 RPM

Engine Oil Level Switch

Eng 2

OK/Low

OK

Engine Oil Life Remaining

Eng 2

0-100%

Varies

Engine Oil Pressure Sensor

Eng 2

Volts

1.5 Volts/Varies

Engine Run Time

All

Hrs, Min, Sec

Varies

Engine Speed

All

0-10,000 RPM

500-700 RPM

EVAP Purge Solenoid Command

Eng 1, EE, FT

0-100%

10-25%

EVAP Test Result

EE

Test Result

Varies

EVAP Test State

EE

Test State

Varies

EVAP Vent Solenoid Command

Eng 1, EE, FT

Not Venting/Venting

Venting

Fail Counter

FF

Counts

Varies

Fuel Alcohol Content

Eng 2

%

Varies

Fuel Comp. Sensor Frequency

Eng 2

Hz

Varies

Fuel Comp. Sensor On Time

Eng 2

mS

Varies

Fuel Level Sensor

Eng 1, EE

0-5 Volts

0.7-2.5 Volts

Fuel Level Sensor Rear Tank, if equipped

Eng 1, EE

0-5 Volts

0.7-2.5 Volts

Fuel Tank Level Remaining

EE

Gallon/Liter

Varies

Fuel Tank Level Remaining

EE

0-100%

Varies

Fuel Tank Pressure Sensor

Eng 1, EE

-32.7 to +14.0 mm/Hg (-17.5 to +7.5 in/H2O)

Varies

Fuel Tank Pressure Sensor

EE

0-5.0 volts

Varies

Fuel Tank Rated Capacity

EE

98 Liters (25.9 Gallons) or 129 Liters (34 Gallons)

Varies with Fuel Tank Option

Fuel Temperature

Eng 2

°C/°F

Varies

Fuel Trim Cell

Eng 1, EE, FT

0-23

19

Fuel Trim Learn

Eng 1, EE, FT

Enabled/Disabled

Enabled, May Toggle

Generator F Terminal Signal

Eng 2

Percent

Varies

Generator L Terminal Signal Command

Eng 2

Off/On

On

HO2S Bank 1 Sensor 1

Eng 1, EE, FT, HO2S

Millivolts

10-1,000 mV and Varying

HO2S Bank 1 Sensor 2

Eng 1, FT, HO2S

Millivolts

10-1,000 mV and Varying

HO2S Bank 2 Sensor 1

Eng 1, EE, FT, HO2S

Millivolts

10-1,000 mV and Varying

HO2S Bank 2 Sensor 2

Eng 1, FT, HO2S

Millivolts

10-1,000 mV and Varying

HO2S Heater BN 1 Sensor 1

HO2S

Amps

Varies

HO2S Heater BN 1 Sensor 2

HO2S

Amps

Varies

HO2S Heater BN 2 Sensor 1

HO2S

Amps

Varies

HO2S Heater BN 2 Sensor 2

HO2S

Amps

Varies

Hot Run Counter

FF

Counts

Varies

IAT Sensor

Eng 1, Eng 2, EE, FT, HO2S

-39 to +140°C (-38 to +284°F)

35°C (91°F) Depends on Ambient Temperature

Ignition 1 Signal

Eng 1, Eng 2, CC, EE, FT, TAC

0-25 Volts

11.5-14.5 Volts

Inj. PWM Bank 1 Average

Eng 2, FT, MF

Milliseconds

2-6

Inj. PWM Bank 2 Average

Eng 2, FT, MF

Milliseconds

2-6

Knock Retard

Eng 1

0.0-16°

Long Term FT Avg. Bn1

FT

Percentage

Near 0%

Long Term FT Avg. Bn2

FT

Percentage

Near 0%

Long Term FT Bank 1

Eng 1, Eng 2, EE, FT, HO2S

Percentage

Near 0%

Long Term FT Bank 2

Eng 1, Eng 2, EE, FT, HO2S

Percentage

Near 0%

Loop Status

Eng 1, 2, EE, FT, HO2S

Open/Closed

Closed

Low Oil Lamp Command

Eng 2

On/Off

Off

MAF Sensor

Eng 1, Eng 2, EE, MF, FT, TAC, HO2S

Grams Per Seconds (g/s)

1-9 g/s @ Idle, Depends on Altitude

15-26 g/s @ 2,500 RPM, Depends on Altitude

MAF Sensor

Eng 2

0-31,999 Hz

2,000-3,000 Hz

MAP Sensor

Eng 1, Eng 2, EE, FT, MF, TAC, HO2S

kPa

20-48 kPa

MAP Sensor

Eng 1, Eng 2, FF/FR

Volts

1.0-2.0 Volts

Varies with Altitude

MIL Command

Eng 2

Off/On

Off

Mileage Since DTC Cleared

Eng 2

kilometers/miles

Varies

Mileage Since First Failure

FF

Counts

Varies

Mileage Since Last Failure

FF

Counts

Varies

Misfire Counter Status

MF

Normal/Invalid

Normal

Misfire Current Cyl. 1-8

MF

0-200 Counts

0

Misfire History Cyl. 1-8

MF

0-65,535 Counts

0

Pass Counter

FF

Counts

Varies

PCM Reset

Eng 1, Eng 2, EE, FT

Yes/No

No

PCM/VCM in VTD Fail Enable

Eng 1

Yes/No

No

Power Enrichment

Eng 1, HO2S

Active/Inactive

Inactive

Reduced Engine Power

Eng 1, CC, TAC

Active/Inactive

Inactive

Short Term FT Avg Bn1

FT

Percentage

Near 0%

Short Term FT Avg Bn2

FT

Percentage

Near 0%

Short Term FT Bank 1

Eng 1, Eng 2, EE, FT, HO2S

Percentage

Near 0%

Short Term FT Bank 2

Eng 1, Eng 2, EE, FT, HO2S

Percentage

Near 0%

Spark

Eng 1, Eng 2, FT, MF, HO2S

Degrees

15-20°

Start Up ECT

Eng 2, EE, FT

C°/F°

Varies

Stop Lamp Pedal Switch

CC, TAC

Applied/Released

Released

TAC/PCM Comm Signal

TAC, CC

OK/Fault

OK

TCC Enable Solenoid Command

Eng 1, Eng 2

On/Off

Off

TCC PWM Solenoid Command

Eng 2

On/Off

Off

TFP Switch

Eng 2, CC, FT

Transmission Gear Position

Varies

Torque Delivered Signal

Eng 2, TAC

N·m lb ft

Varies

Torque Request Signal

Eng 2, TAC

N·m lb ft

406 N·m 299 lb ft

TP Desired Angle

Eng 1, Eng 2, EE, TAC, CC

0-100%

5.5%

TP Indicated Angle

All

0-100%

5.5%

TP Sensor 1

TAC

0-5.0 Volts

0.4-0.9 Volts

TP Sensor 1

TAC

0-100%

Varies near 0%

TP Sensor 2

TAC

5.0-0 Volts

Volts

TP Sensor 2

TAC

100-0%

Varies

TP Sensors 1 and 2

TAC

Agree/Disagree

Agree

TR Switch

CC, FT

Transmission Gear

Varies

Traction Control Signal

Eng 2, CC, TAC

Active/Inactive

Inactive

Vehicle Speed Sensor

All

km/h

mph

0

VTD Auto Learn Timer

Eng 1

Active/Inactive

Inactive

VTD Fuel Disable

Eng 1

Active/Inactive

Inactive

VTD Fuel Disable Until Ign. Off

Eng 1

Yes/No

No

Warm-Ups w/o Emission Faults

Eng 2

0-255 Counts

Varies

Warm-Ups w/o Non-Emission Faults

Eng 2

0-255 Counts

Varies