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 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 conditions are determined:

    •  The Diagnostic System Check - Vehicle is completed.
    •  There are no diagnostic trouble codes (DTCs).
    • The on-board diagnostics are functioning correctly.

Scan tool values from an engine that is operating correctly may be used for comparison with the engine you are diagnosing. The Engine Scan Tool Data List represents the values that would be seen on a normal operating engine.

Important: Do not use a scan tool that displays faulty data. The scan tool concern should be reported to the manufacturer. Use of a faulty scan tool may result in misdiagnosis and unnecessary parts replacement.

Only the parameters listed below are referenced in this service information 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 is located on the scan tool. Review 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 data lists indicated below.

CH: Cooling/HVAC Data

CMP: CMP Actuator Data

CT: Cruise/Traction Data

Eng: Engine Data

ET: Electrical/Theft Data

EVAP: EVAP Data

FF: Freeze Frame Data

FR: Failure Records

FT: Fuel Trim Data

HO2S: HO2S Data

Ign: Ignition Data

IM: I/M Data

IND: Induction Data

IPC: Instrument Panel Cluster Data

MF: Misfire Data

TAC: TAC Data

Trans: Auto Trans Data

Scan Tool Data List

Scan Tool Parameter

Data List

Parameter Range/Units

Typical Data Values

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

5-Volt Reference 1, 2, or 3 Circuit Status

EVAP, IGN, IND, TAC, CH

OK/Fault

OK

A/C Disengage 1-8 History

Cooling/HVAC

Reason for A/C Disengagement

Varies

A/C High Side Pressure

Cooling/HVAC

0-5 Volts

Varies

A/C High Side Pressure

Cooling/HVAC

kPa/psi

Varies

A/C Off for WOT

Cooling/HVAC

Yes/No

No

A/C Pressure Disable

Cooling/HVAC

Yes/No

No

A/C Relay Circuit Status

Cooling/HVAC

OK/Fault/Indeterminate

OK

A/C Relay Command

Eng, TAC, CH, IND, MF

On/Off

Off

A/C Request Signal

Cooling/HVAC

Yes/No

No

Air Flow Calculated

ENG, EVAP, FT, HO2S, IND, MF, TAC

g/s

--

Air Fuel Ratio

ENG, FT, HO2S, IND

14.7:1

Varies

Ambient Air Temperature

ENG, EVAP

°C/°F

Varies

APP Indicated Angle

CMP,CT, Eng, ET, EVAP, FT, HO2S, Ign, IND, MF, TAC, Trans

0-100%

0%

APP Sensors

TAC

0-100%

0%

APP Sensor 1

TAC

0.9-4.5 Volts

1 Volt

APP Sensor 2

TAC

0.40-2.25 Volts

0.4 Volt

APP Sensor 1 and 2

TAC

Agree/Disagree

Agree

BARO

CMP , Eng, EVAP, FT, HO2S, Ign,IM, IND, Trans

65-104 kPa (8-16 psi)

Varies with altitude

BARO

IND

Volts

Varies

Brake Pedal Signal Status

CT, Eng, ET, TAC, Trans

Valid/Invalid

Valid

Calculated ECT - Closed Loop Fuel Control

CH

-39 to +40°C (-38 to +104°F)

40°C (104°F)

Calculated ECT - Thermostat Diagnosis

CH

-39 to +140°C (-38 to +284°F)

89°C (192°F)

Calc. TWC Temp. Bank 1 and 2 Sensor 1 and 2

FT, MF

Temperature

Varies

Catalytic Converter Protection Active

FT, HO2S

Yes/No

No

Catalyst Monitor Complete This Ignition

IM

Yes/No

Varies

Catalyst Monitor Enabled this Ignition

IM

Yes/No

Varies

CKP Resync Counter

Ign

Counts

0 Counts

CKP Active Counter

Ign

Counts

0 Counts

CMP Sensor

CMP, IGN, MF

RPM

Engine idle speed

Cold Startup

ENG, EVAP, IM

YES/NO

Varies

Crank Request Signal

ET

Yes/No

No

Cruise Control Active

ENG, TAC

Active/Inactive

Inactive

Cruise Control Active

CT, Eng, IPC, TAC,

Yes/No

No

Cruise Disengage 1-8 History

CT

Reason

Varies

Cruise Inhibited

CT

Yes/No

No

Cruise On/Off Switch

CT

On/Off

Off

Cruise Resume/Accel. Switch

CT

ON/OFF

OFF

Cruise Set/Coast Switch

CT

ON/OFF

OFF

Cylinder 1-6 IC Circuit Status

MF

OK/Fault/Indeterminate

OK

Cylinder 1-6 Injector Circuit Status

MF

OK/Fault/Indeterminate

OK

Cylinder 1-6 Knock Retard

Ign

Degree

0 Degrees

Decel. Fuel Cutoff

Eng, FT, HO2S

Active/Inactive

Inactive

Desired Exh. CMP Bank 1 or 2

CMP

Degree

Varies

Desired Idle Speed

Eng, EVAP, CMP, CT, IND

0-7,000 RPM

650 RPM

Desired Int. CMP Bank 1 or 2

CMP

Degrees

Varies

Distance Since DTC Cleared

ENG

Miles/Kilometers

Varies

DTC Set This Ignition

Eng

Yes/No

No

EC Ignition Relay Command

Eng, ET,TAC

On/Off

On

EC Ignition Relay Circuit Status

ET

OK/Fault/Indeterminate

OK

EC Ignition Relay Feedback Signal

Eng, TAC, ET

0-25.5 Volts

12.0-14.5 Volts

ECM in VTD Fail Enable

ET

Yes/No

No

ECT Sensor

ALL

-39°C to +140°C (-38°F to +284°F)

Varies

Engine Load

CH, CMP, Eng, EVAP, FF, FR, FT, ,HO2S, Ign, IND, MF, TAC, Trans

0-99%

25-45% - Idle

40-60% - 2500 RPM

Engine OFF EVAP Test Conditions Met

EVAP

Yes/No

Varies

Engine Off Time

EVAP, IM

0:00:00 Seconds

Varies

Engine Oil Life Remaining

CMP, IPC

%

Varies

Engine Oil Pressure Sensor

IPC

1-5 Volts

Varies

Engine Oil Pressure Sensor

CMP, Eng, ET, IPC, MF,

kPa/psi

Varies

Engine Oil Temperature Calculated

CH, CMP, IPC

°C (°F)

Varies

Engine Run Time

Eng, Ign, EVAP, FT, HO2S, IM, MF, TAC, CMP, CH, CT, IND, Trans

0:00:00

Varies

Engine Speed

CH, CMP, CT, Eng, ET, EVAP, FF, FR, FT, ,HO2S, Ign, IND, IPC, MF, TAC, Trans

RPM

575-700 RPM

EVAP Fault History

EVAP

Vacuum/Purge Valve Leak/Small Leak/Weak Vacuum/No Test Result

No Test Result

EVAP Monitor Complete This Ignition

IM

Yes/No

Varies

EVAP Monitor Enabled This Ignition

IM

Yes/No

Varies

EVAP Purge Solenoid Circuit Status

EVAP

OK/Fault/Indeterminate

OK

EVAP Purge Solenoid Command

Eng, EVAP, FT, H02S

0-100%

Varies

EVAP Vent Solenoid Circuit Status

EVAP

OK/Fault/Indeterminate

OK

EVAP Vent Solenoid Command

Eng, EVAP, FT

Venting/Not Venting

Venting

Exh. CMP Angle Bank 1 or 2

CMP

Degrees

Varies

Exh. CMP Bank 1 or Bank 2 Active Counter

CMP, IGN

Counts

Varies

Exh. CMP Bank 1 or 2 Command

CMP

0-99%

Varies

Exh. CMP Angle Bank 1 or 2 Variance

CMP

Degrees

Varies

Exh. CMP Solenoid Bn. 1 or 2 Circuit Status

CMP

OK/Fault/Indeterminate

OK

FC Relay 1 Circuit Status

CH

OK/Fault/Indeterminate

OK

FC Relay 2 and 3 Circuit Status

CH

OK/Fault/Indeterminate

OK

FC Relay 1 Command

CH

On/Off

Varies

FC Relay 2 and 3 Command

CH

On/Off

Varies

Fuel Level Sensor Left Tank (Secondary) Fuel Level Sensor Right Tank (Primary)

EVAP

0-5 Volts

Varies

Fuel Pump Relay Circuit Status

Eng

OK/Fault/Indeterminate

OK

Fuel Pump Relay Command

Eng

On/Off

On

Fuel Tank Level Remaining

Eng, EVAP, FT, IM, IPC MF,

Liter/Gallon/Percent

Varies

Fuel Tank Pressure Sensor

Eng, EVAP

in H2O/mm Hg

Varies

Fuel Tank Pressure Sensor

EVAP

0-5 Volts

Varies

Fuel Tank Rated Capacity

EVAP

Liter/Gallon

19.9 Gallons (75.3 Liters)

Fuel Trim Learn

FT

Enabled/Disabled

Enabled

GEN L-Terminal Signal Command

ET

ON/OFF

ON

Generator F-Terminal Signal

ET

0-100%

Varies

HO2S Bank 1 or 2 Sensor 1

Eng, EVAP, FT, HO2S, IND

0-1,006 mV

Varies 400-700 mV

HO2S Bank 1 or 2 Sensor 2

Eng, EVAP, FT, HO2S, IND

0-1,006 mV

Varies 400-700 mV

HO2S Heater Monitor Complete This Ignition

IM

Yes/No

Varies

HO2S Heater Monitor Enabled This Ignition

IM

Yes/No

Varies

HO2S Htr. Bn. 1 or 2 Sensor 1 or 2 Circuit Status

H02S

OK/Fault/Indeterminate

OK

HO2S Bank 1 or 2 Sensor 1 or 2 Heater Command

HO2S

0-99%

Varies

HO2S Bank 1 or 2 Sensor 1 or 2 Heater Command

HO2S

ON/OFF

ON

HO2S/O2S Monitor Complete This Ignition

IM

Yes/No

Varies

HO2S/O2S Monitor Enabled This Ignition

IM

Yes/No

Varies

HO2S Sensing Element Bn. 1 or 2 Sensor 1

HO2S

Ohms

70-90 Ohms

Depends on Temperature

HO2S Sensing Element Bn. 1 or 2 Sensor 2

HO2S

Ohms

20-300 Ohms

Depends on Temperature

IAT Sensor

CH, CMP, Eng, EVAP, FF, FR, FT, HO2S, Ign, IM, IND, MF, TAC,Trans

-39° to +140°C (-38° to +284°F)

Varies

Ignition Off Time

ENG, EVAP, IM

0:00:00

Varies

Ignition 0 Signal

Eng, ET, Ign, IM, IPC, TAC

On/Off

On

Ignition 1 Signal

ALL

Volts

B+

Ignition 1 Signal

Eng, ET, EVAP

On/Off

On

IMRC Solenoid Circuit Status

IND

OK/Fault/Indeterminate

OK

IMRC Solenoid Command

IND

On/Off

Off

Initial Brake Apply Signal

CT, Eng, ET, IM, TAC, Trans

Applied/Released

Released

Injector 1-6 Command

FT, MF

ms

Varies

Injector 1-6 Disabled Due to Misfire

FT, MF

YES/NO

NO

Int. CMP Angle Bank 1 or 2

CMP

Degrees

Varies

Int. CMP Bank 1 or Bank 2 Active Counter

CMP, IGN

Counts

Varies

Int. CMP Angle Bank 1 or 2 Variance

CMP

Degrees

Varies

Int. CMP Bank 1 or 2 Command

CMP

0-99%

Varies

Int. CMP Solenoid Bn. 1 or 2 Circuit Status

CMP

OK/Fault/Indeterminate

OK

Knock Detected Cyl. 1-6

IGN

YES/NO

NO

Knock Retard

Ign

Degrees

Varies

KS 1 or 2 Signal

Ign

Volts

Varies

Long Term FT Bank 1 or Bank 2

CMP, ENG, EVAP, FT, HO2S

-100 to +100%

7-9%

Loop Status Bn 1 or 2 Sen. 1

Eng, EVAP, FF, FR, FT, HO2S,

Open Loop/Closed Loop

Closed Loop

Loop Status Bn 1 or 2 Sen. 2

Eng, EVAP, FF, FR, FT, HO2S,

Open Loop/Closed Loop

Open Loop

LT FT Bn. 1 or Bn. 2 Idle/Decel.

Eng, EVAP, FT, HO2S

-100% to +100%

0%

MAF Performance Test

IND, TAC

OK/Fault

OK

MAF Sensor

CMP, Eng, EVAP, FF, FR, FT, HO2S, Ign, IND, MF, TAC, Trans

0-655 g/s

3.4-6.3 g/s

MAF Sensor

IND

0-9999 Hz

28 Hz

MIL Circuit Status

Eng, IPC

OK/Fault/Indeterminate

OK

MIL Command

Eng, IPC, IM

On/Off

Off

Mil Requested by DTC

CMP, Eng, EVAP, FF, FR, FT, IM, HO2S, Ign, IND, MF, TAC, Trans

Yes/No

No

Mileage Since DTC First Failure

FF, FR

km - miles

Varies

Mileage Since DTC Last Failure

FF, FR

km - miles

Varies

Mileage Since MIL Requested

FF, FR

km - miles

Varies

Misfire Current Cyl. 1-6

MF

0-255 Counts

0

Misfire History Cyl. 1-6

MF

0-65,535 Counts

0

Moderate Brake Apply Signal

CT, TAC

Applied/Released

Released

PNP Switch

Eng

Park/Neutral/In Gear

P/N

Power Enrichment

Eng, FT, HO2S, MF

Active/Inactive

Inactive

Reduced Engine Power

TAC

Active/Inactive

Inactive

RVS Disable 1-8 History

ET

None

Varies

Short Term FT Bank 1 or Bank 2

Eng, EVAP, FT, HO2S, FF, FR

-25% to +25%

-3% to +3%

Spark

Eng, Ign, FT, HO2S, MF, CH, CT, IND, FF, FR

-20 to +40 Degrees

2-10 Degrees

Starter Relay Circuit Status

ET

OK/Fault/Indeterminate

OK

Starter Relay Command

CT, ET

On/Off

Off

Start Up ECT

CH, EVAP, HO2S, IM

-39° to +140°C (-38° to +284°F)

Varies

Start Up IAT

CH, EVAP, HO2S, IM

-39° to +140°C (-38° to +284°F)

Varies

Stoplamp Pedal Switch

CT, ET, IM, TAC

Applied/Released

Released

System Power Mode

Eng, ET, EVAP, TAC

Off, Accessory, RAP, Run, or Crank Request

Run

TAC Forced Engine Shutdown

TAC

YES/NO

NO

TAC Motor

TAC

Enabled/Disabled

Enabled

TAC System Learned Counts

TAC

0-11 Counts

11

TCC Status

MF

Locked/Unlocked

Unlocked

TCM Requested Torque

Trans

N·m/lb ft

Varies

TCM Torque Increase

CT, TAC, Trans

Yes/No

NO

TCS Torque Increase

CT, TAC

Yes/No

NO

TCS Torque Reduction Active

CT, TAC, Trans

Yes/No

NO

TCM Torque Reduction Active

CT, TAC, Trans

Yes/No

NO

TCS Torque Delivered Signal

CT, TAC

0-100%

0%

TCS Torque Request Signal

CT, TAC, Trans

0-100%

90-98%

Total Fuel Trim Avg. Bank 1 or Bank 2

EVAP, FT, HO2S

-100 to +100%

Varies

Total Knock Retard

IGN, CH

Degrees

0

Total Misfire Count

MF

Counts

0

TP Desired Angle

Eng, EVAP, TAC

0-100%

Varies

TP Indicated Angle

CMP, CT, Eng, EVAP, FT, ,FF, FR, HO2S, Ign, IND MF, TAC, Trans

0-100%

Varies

TP Performance Test

IND, TAC, FT

Active/Inactive

Inactive

TP Sensor 1

TAC

4.5-5.0 Volts

4.0

0.5-4.50 Volts

TP Sensor 1 Learned Minimum

TAC

0-5 Volts

0.5-4.50 Volts

TP Sensor 2

TAC

0-5 Volts

5.0-1.0 Volts

TP Sensor 2 Learned Minimum

TAC

0-5 Volts

5.0-1.0 Volts

TP Sensors 1 and 2

TAC

Agree/Disagree

Agree

Traction Control Status

TAC, CT

Active/Inactive

Inactive

Vehicle Speed Sensor

All

Km/h

mph

Varies

Volumetric Efficiency

Eng, Ign, EVAP, FT, HO2S, MF, TAC, CMP, CH, Trans

0-100%

5-25% - Idle and at 2,500 RPM

VTD Auto. Learn Timer

ET

Active/Inactive

Inactive

VTD Fuel Disable

ET

Active/Inactive

Inactive

VTD Fuel Enabled

ET

Yes/No

Yes

VTD Fuel Disable Untill Ign. Off

ET

Yes/No

No

VTD Password learned

ET

Yes/No

Yes

Warm Ups Since DTC Cleared

Eng

Counts

Varies

Wide Open Throttle

TAC

Yes/No

NO