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.
    • 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 except Output Driver data.

Eng: Engine Data List

EE: Enhanced Evaporative Emission (EVAP) Data

FT: Fuel Trim Data List

H02S: Heated Oxygen Sensor (HO2S) Data List

Ign: Ignition System Data List

MF: Misfire Data List

OD: Output Driver Data List

TAC: Throttle Actuator Control (TAC) Data List

Scan Tool Parameter

Data List

Parameter Range/Units

Typical Data Values

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

5-Volt Reference 1 Circuit Status

EE, Eng, Ign, TAC

OK/Fault

OK

5-Volt Reference 2 Circuit Status

EE, Eng, Ign, TAC

OK/Fault

OK

5-Volt Reference 1

EE, Eng, Ign, TAC

Volts

4.5 V

5-Volt Reference 2

EE, Eng, Ign, TAC

Volts

4.5 V

A/C Relay Circuit Status

OD

OK, Incomplete, Short B+, Short Gnd/Open

OK/Incomplete

A/C Relay Command

Eng , MF, TAC

On/Off

Varies

Air Flow Calculated

EE, Eng, FT, HO2S, MF, TAC

Grams Per Seconds (g/s)

1-9 g/s @ idle

Air Fuel Ratio

Eng, FT, HO2S

X:1

14.7:1

Ambient Air Temperature

Eng

°C/°F

Varies

APP Indicated Angle

EE, Eng, FT, HO2S, Ign, MF, TAC

0-100%

0

APP Sensor 1

TAC

0-5.0 Volts

0.4-1.0 Volt

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

APP Sensor 1 Indicated Position

TAC

%

0%

APP Sensor 2 Indicated Position

TAC

%

--

APP Sensors

TAC

%

0%

BARO

EE, Eng, FT, HO2S, Ign

kPa

50-104 kPa/ Varies w/Altitude

BPP Circuit Signal

TAC

Applied/Released

--

Calculated TWC Temp Bank 1

FT, MF

Degrees C/F

315-427°C (600-800°F)

Calculated TWC Temp Bank 2

FT, MF

Degrees C/F

315-427°C (600-800°F)

Catalytic Converter Protection Active

FT, HO2S

Yes/No

No

CKP Active Counter

Ign

0-250 Counts

Varies

CKP Resync Counter

Ign

Counts

0

CKP Sensor

Eng, Ign

RPM

500-700 RPM

CMP Active Counter

Ign

0-250 Counts

Varies

CMP Sensor

Eng, Ign, MF

RPM

1,000-1,400 RPM

Cold Start-Up

Eng, EE

Yes/No

Varies

Cruise Control Active

Eng, TAC

Active/Inactive

Inactive

Cycles of Misfire Data

MF

0-100 Counts

Varies

Cylinder 1-8 IC Circuit Status

OD

OK, Incomplete, Short B+, Short Gnd/Open

OK

Cylinder 1-8 Injector Circuit Status

OD

OK, Incomplete, Short B+, Short Gnd/Open

OK

Decel Fuel Cutoff

Eng, FT, HO2S

Active/Inactive

Inactive

Desired Idle Speed

EE, Eng, TAC

RPM

ECM Controlled

Distance Since DTC Cleared

Eng

km/miles

Varies

EC Ignition Relay Circuit Status

OD

OK, Incomplete, Short B+, Short Gnd/Open

OK/Incomplete

EC Ignition Relay Command

Eng, TAC

On/Off

On

EC Ignition Relay Feedback

Eng, TAC

Volts

2.25-2.95 Volts

ECM Reset

EE, Eng, Ign

Yes/No

No

ECT Sensor

All

-39 to +140°C (-38 to +284°F)

88-105°C (190-221°F)

Engine Load

All

0-100%

18% @ Idle

21% @ 2500 RPM

Engine Off EVAP Test Connections Met

EE

Yes/No

Yes

Engine Oil Level Switch

Eng

OK/Low

OK

Engine Oil Pressure Sensor

Eng, MF

PSI

30

Engine Oil Pressure Sensor

EVAP

Volts

1.5

Engine Run Time

All

Hrs, Min, Sec

Varies

Engine Speed

All

0-10,000 RPM

500-700 RPM

Engine Speed Circuit Status

OD

OK, Incomplete, Short B+, Short Gnd/Open

OK

EVAP Purge Solenoid Circuit Status

OD

OK, Incomplete, Short B+, Short Gnd/Open

OK/Incomplete

EVAP Purge Solenoid Command

EE, Eng, FT, HO2S

0-100%

10-25%

EVAP Vent Solenoid Circuit Status

OD

OK, Incomplete, Short B+, Short Gnd/Open

OK/Incomplete

EVAP Vent Solenoid Command

EE, Eng, FT

Not Venting/Venting

Venting

FC Circuit Status

OD

OK, Incomplete, Short B+, Short Gnd/Open

OK/Incomplete

Fuel Level Sensor

EE

0-5 Volts

0.7-2.5 Volts

Fuel Pump Relay Circuit Status

OD

OK, Incomplete, Short B+, Short Gnd/Open

OK/Incomplete

Fuel Pump Relay Command

Eng, FT

On/Off

ON

Fuel Tank Level Remaining

Eng, MF

0-100%

Varies

Fuel Tank Pressure Sensor

EE, Eng

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

Varies

Fuel Tank Pressure Sensor

EE, Eng

0-5.0 Volts

Varies

Fuel Tank Rated Capacity

EE

98 Liters (25.9 Gallons) or 96.2 Liters (25 Gallons)

Varies with Fuel Tank Option

Fuel Trim Cell

EE, Eng, FT

0-23

19

Fuel Trim Learn

EE, Eng, FT

Enabled/Disabled

Enabled, May Toggle

Fuel Volatility

EE, FT, HO2S

Low/Moderate/High

Varies

HO2S Bank 1 Sensor 1

EE, Eng, FT, HO2S

Millivolts

10-1,000 mV and Varying

HO2S Bank 1 Sensor 2

Eng, FT, HO2S

Millivolts

10-1,000 mV and Varying

HO2S Bank 2 Sensor 1

EE, Eng, FT, HO2S

Millivolts

10-1,000 mV and Varying

HO2S Bank 2 Sensor 2

Eng, FT, HO2S

Millivolts

10-1,000 mV and Varying

HO2S BN 1 Sensor 1 Heater

HO2S

Amps

0.7-0.9 Amps

HO2S BN 1 Sensor 2 Heater

HO2S

Amps

0.4-0.6 Amps

HO2S BN 2 Sensor 1 Heater

HO2S

Amps

0.7-0.9 Amps

HO2S BN 2 Sensor 2 Heater

HO2S

Amps

0.4-0.6 Amps

HO2S BNK 1 Sen 1 Heater Circuit Status

OD

OK, Incomplete, Short B+, Short Gnd/Open

OK/Incomplete

HO2S BNK 1 Sen 2 Heater Circuit Status

OD

OK, Incomplete, Short B+, Short Gnd/Open

OK/Incomplete

HO2S BNK 2 Sen 1 Heater Circuit Status

OD

OK, Incomplete, Short B+, Short Gnd/Open

OK/Incomplete

HO2S BNK 2 Sen 2 Heater Circuit Status

OD

OK, Incomplete, Short B+, Short Gnd/Open

OK/Incomplete

HO2S Bnk 1 Sensor 1 Heater Command

HO2S

On/Off

ON

HO2S Bnk 1 Sensor 1 Heater Command

HO2S

%

100%

HO2S Bnk 1 Sensor 2 Heater Command

HO2S

On/Off

ON

HO2S Bnk 1 Sensor 2 Heater Command

HO2S

%

100%

HO2S Bnk 2 Sensor 1 Heater Command

HO2S

On/Off

ON

HO2S Bnk 2 Sensor 1 Heater Command

HO2S

%

100%

HO2S Bnk 2 Sensor 2 Heater Command

HO2S

On/Off

ON

HO2S Bnk 2 Sensor 2 Heater Command

HO2S

%

100%

Hot Open Loop

FT, HO2S

Active/Inactive

Inactive

IAT Sensor

All

-39 to +140°C (-38 to +284°F)

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

Ignition Accessory Signal

Eng, TAC

On/Off

ON

Ignition 1 Signal

All

0-25 Volts

11.5-14.5 Volts

Ignition Off Timer

Eng

Seconds, Minutes, Hours

Varies

Inj. PWM Bank 1

Eng, FT, HO2S

Milliseconds

2-6

Inj. PWM Bank 2

Eng, FT, HO2S

Milliseconds

2-6

Knock Retard

Ign

0.0-16°

KS Active Counter

Ign

Counts

Varies

KS Bank 1 Circuit Status

Ign

OK/Fault/Incomplete

OK/Incomplete

KS Bank 2 Circuit Status

Ign

OK/Fault/Incomplete

OK/Incomplete

KS Module Status

Ign

OK/Fault/Incomplete

OK/Incomplete

Long Term FT Bank 1

EE, Eng, FT, HO2S

Percentage

Near 0%

Long Term FT Bank 2

EE, Eng, FT, HO2S

Percentage

Near 0%

Loop Status

EE, Eng, FT, HO2S

Open/Closed

Closed

MAF Sensor

EE, Eng, FT, HO2S, Ign, MF, TAC,

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

EE, Eng, FT, HO2S, MF

0-31,999 Hz

1,150-1,350 Hz

MAP Sensor

EE, Eng, FT, HO2S, Ign, MF, TAC,

kPa

20-48 kPa

MAP Sensor

Eng, FT, HO2S, MF, TAC

Volts

1.0-2.0 Volts

Varies with Altitude

MIL Circuit Status

OD

OK, Incomplete, Short B+, Short Gnd/Open

OK/Incomplete

MIL Command

EE, Eng, Ign

Off/On

Off

MIL Requested by DTC

EE, Eng, Ign

Yes/No

No

Misfire Current Cyl. 1-8

MF

0-200 Counts

0

Misfire History Cyl. 1-8

MF

0-65,535 Counts

0

PNP Switch

Eng

P/N

Yes/No in gear

P/N

Power Enrichment

Eng, FT, HO2S, MF

Active/Inactive

Inactive

Reduced Engine Power

TAC

Active/Inactive

Inactive

Short Term FT Bank 1

EE, Eng, FT, HO2S

Percentage

Near 0%

Short Term FT Bank 2

EE, Eng, FT, HO2S

Percentage

Near 0%

Spark

Eng, FT, HO2S, Ign, MF

Degrees

10-17°

Starter Relay Circuit Status

OD

OK, Incomplete, Short B+, Short Gnd/Open

OK/Incomplete

Start-Up ECT

EE, FT

°C/°F

Varies

Start-Up IAT

EE, HO2S

°C/°F

Varies

TAC Forced Engine Shutdown

TAC

Yes/No

No

TAC Motor

TAC

Enabled/Disabled

Enabled

TAC Motor Command

TAC

0-100%

15-35%

TCC/Cruise Brake Pedal

Eng

Applied/Released/Invalid

Released

TCC/Cruise Brake Pedal Switch

TAC

Applied/Released/Invalid

Released

TCS Circuit Status

OD

OK, Incomplete, Short B+, Short Gnd/Open

OK/Incomplete

TCS Torque Request Signal

TAC

0-100%

100%

Torque Delivered Signal

TAC

0-100%

5-15%

Torque Management Spark Retard

Ign

Degrees

Total Knock Retard

Ign

Degrees

Total Misfire

MF

Counts

Varies

TP Desired Angle

TAC

0-100%

5.5%

TP Indicated Angle

EE, Eng, FT, HO2S, Ign, MF, TAC

0-100%

5.5%

TP Sensor 1

TAC

0-5.0 Volts

4.1-4.95 Volts

TP Sensor 1

TAC

0-100%

Varies near 5%

TP Sensor 1 Learned Minimum

TAC

Volts

.55

TP Sensor 2

TAC

5.0-0 Volts

0.4-0.85 V

TP Sensor 2

TAC

100-0%

Varies near 5%

TP Sensor 2 Learned minimum

TAC

Volts

.55

TP Sensors 1 and 2

TAC

Agree/Disagree

Agree

TP Sensor 1 Indicated Position

TAC

%

5%

TP Sensor 2 Indicated Position

TAC

%

5%

TWC Temperature Calculated

FT, MF

Degrees C/F

570°C (1,075°F)

Vacuum Calculated

EE, Eng, FT, HO2S

kPa/in Hg

59 kPa/16 in Hg

Vehicle Speed Circuit Status

OD

OK, Incomplete, Short B+, Short Gnd/Open

OK/Incomplete

Vehicle Speed Circuit 2 Status

OD

OK, Incomplete, Short B+, Short Gnd/Open

OK/Incomplete

Vehicle Speed Sensor

EE, Eng, FT, HO2S, Ign, MF, TAC

km/h

mph

0

Warm-Ups w/o Emission Faults

Eng

0-255 Counts

Varies

Warm-Ups w/o Non-Emission Faults

Eng

0-255 Counts

Varies

Warm-Ups Since DTC Cleared

Eng

Counts

Varies

Wide Open Throttle

TAC

Yes/No

No