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 Parameter

Data List

Parameter Range/Units

Typical Data Values

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

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

On/Off

Off

A/C Request Signal

Cooling/HVAC

Yes/No

No

APP Indicated Angle

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

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

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

65-104 kPa (8-16 psi)

Varies with altitude

BARO

Eng, IND

Volts

Varies

Brake Pedal Signal Status

Eng, CT, ET, Trans

Valid/Invalid

Valid

Catalytic Converter Protection Active

FT, MF

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, MF

Counts

0 Counts

Commanded A/F Equivalence Ratio

FT, HO2S, IND

14.7:1

Varies

Component Monitor Enable This Ignition

IM

Yes/No

Varies

Crank Request Signal

ET

Yes/No

No

Cruise Control Active

Eng, TAC, CT, IPC

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

Active/Inactive

Inactive

Cruise Set/Coast Switch

CT

Active/Inactive

Inactive

Current Gear

Eng, ET, IPC, FT, MF

P/N/Reverse/1st-5th

P/N

Cycles of Misfire Data

MF

0-200 counts

Varies

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 HO2S 1

HO2S

Lambda

Varies

Desired Idle Speed

Eng, EVAP, CMP, TAC, CT, IND

0-7,000 RPM

650 RPM

Desired Int. CMP Bank 1 or 2

CMP

Degrees

Varies

DTC Set This Ignition

Eng

Yes/No

No

EC Ignition Relay Command

Eng, TAC, ET

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 Reset

Eng, EVAP

Yes/No

No

ECM in VTD Fail Enable

ET

Yes/No

No

ECT Sensor

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

-39°C to +140°C (-38°F to +284°F)

Varies

Engine Load

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

Eng, CMP

OK/Low

OK

Engine Oil Life Remaining

CMP

%

Varies

Engine Oil Pressure Sensor

Eng, MF

1-5 Volts

Varies

Engine Oil Pressure Sensor

MF, CMP

kPa/psi

Varies

Engine Oil Temperature Sensor

CMP,CH, 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

ALL

RPM

575-700 RPM

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

Eng, CMP

Degrees

Varies

Exh. CMP Angle Bank 1 or 2 Variance

CMP

Degrees

Varies

Exh. CMP Bank 1 or 2 Command

CMP

0-99%

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

EVAP

0-100%

Varies

Fuel Level Sensor

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, IM, MF, FT, CMP, IPC

Liter/Gallon

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

17.8 Gallons (67.3 Liters)

Fuel Trim Learn

EVAP, FT, HO2S

Enabled/Disabled

Enabled

HO2S 1

Eng, EVAP, FT, HO2S, IND

Lambda

1.0 Lambda

HO2S 2

Eng, FT, HO2S

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 1 or 2 Heater Circuit Status

H02S

OK/Fault/Indeterminate

OK

HO2S 1 or 2 Heater Command

HO2S

0-99%

Varies

HO2S/O2S Monitor Complete This Ignition

IM

Yes/No

Varies

HO2S/O2S Monitor Enabled This Ignition

IM

Yes/No

Varies

HO2S 1 Sensing Element

HO2S

Ohms

70-90 Ohms

Depends on Temperature

HO2S 2 Sensing Element

HO2S

Ohms

20-300 Ohms

Depends on Temperature

HO2S Sensor 1 Module Signal

HO2S

1-5 Volts

Varies

IAT Sensor

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

-39° to +140°C (-38° to +284°F)

Varies

Ignition 0 Signal

Eng,TAC, ET, IPC

On/Off

On

Ignition 1 Signal

Eng, EVAP, ET

Volts

On

Ignition 1 Signal

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

On/Off

On

Injector 1-6 Command

FT, MF

ms

Varies

Int. Brake Apply Signal

IM

Applied/Released

Released

Int. CMP Angle Bank 1 or 2

CMP

Degrees

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 Retard

Ign

Degrees

Varies

KS 1 or 2 Signal

Ign

Volts

Varies

Loop Status Sensor 1 or 2

Eng, EVAP, FT, HO2S, FF, FR

Open Loop/Closed Loop

Closed Loop

Low EOP Indicator Command

IPC

On/Off

Off

LT FT Cruise/Accel.

Eng, EVAP, FT, HO2S

-100% to +100%

0%

LT FT Idle/Decel.

Eng, EVAP, FT, HO2S

-100% to +100%

0%

MAF Sensor

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

0-655 g/s

3.4-6.3 g/s

MAF Sensor

IND

0-5 Volts

0.9-1.7 Volts

MIL Circuit Status

Eng, IPC

OK/Fault/Indeterminate

OK

MIL Command

Eng, IPC, IM

On/Off

Off

Mil Requested by DTC

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

Yes/No

No

Mileage Since DTC Cleared

Eng, FF, FR

km - miles

Varies

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

TAC

Applied/Released

Released

PNP Switch

Eng

Park/Neutral/In Gear

P/N

Power Enrichment

Eng, FT, HO2S, CMP

Active/Inactive

Inactive

Reduced Engine Power

TAC

Active/Inactive

Inactive

RVS Disable 1-8 History

ET

None

Varies

Short Term FT

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

ET

On/Off

Off

Start Up ECT

EVAP,, HO2S, IM

-39° to +140°C (-38° to +284°F)

Varies

Start Up IAT

EVAP, HO2S, IM

-39° to +140°C (-38° to +284°F)

Varies

Stoplamp Pedal Switch

TAC, IM

Applied/Released

Released

System Power Mode

Eng, EVAP, TAC

Off, Accessory, RAP, Run, or Crank Request

Run

TAC Circuit Status

TAC

OK/Fault/Indeterminate

OK

TAC System Learned Counts

TAC

0-11 Counts

0

TCC Status

MF

Locked/Unlocked

Unlocked

TCM Requested Torque

TAC, Trans

N·m/lb ft

Varies

TCM Torque Increase

TAC, Trans

Yes/No

Varies

TCS Torque Increase

TAC

Yes/No

Varies

TCS Torque Reduction Active

TAC, Trans

Yes/No

Varies

TCM Torque Reduction Active

TAC, Trans

Yes/No

Varies

Torque Delivered Signal

FT, TAC

0-100%

Varies

Torque Request Signal

FT, TAC, Trans

0-100%

90-98%

Total Fuel Trim Average

EVAP, FT, HO2S

-100 to +100%

Varies

Total Misfire Count

MF

Counts

0

TP Desired Angle

Eng, EVAP, TAC

0-100%

Varies

TP Indicated Angle

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

0-100%

Varies

TP Sensor 1

TAC

0-5 Volts

0.5-0.8 Volts

TP Sensor 1 Learned Minimum

TAC

0-5 Volts

0-0.6 Volts

TP Sensor 2

TAC

0-5 Volts

4.7-4.1 Volts

TP Sensor 2 Learned Minimum

TAC

0-5 Volts

5-3.7 Volts

TP Sensors 1 and 2

TAC

Agree/Disagree

Agree

Traction Control Status

TAC

Active/Inactive

Inactive

TWC Temperature Calculated

FT, MF

Temperature

Varies

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 Disable Until Ign. Off

ET

Yes/No

No

VTD Password learned

ET

Yes/No

Yes

Warm Ups Since DTC Cleared

Eng

Counts

Varies