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.

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.

Important: 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. 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:

Eng: Engine data

EGR: Exhaust gas recirculation (EGR) data

EVAP: Evaporative emission (EVAP) data

FUEL TRIM: Fuel trim data

HO2S: Heated oxygen sensor (HO2S) data

Ignition: Ignition system data

Misfire: Misfire data

ODD: Output driver data

TAC Output: Throttle actuator control data

Scan Tool Parameter

Data List

Units Displayed

Typical Data Value

Engine Idling/Radiator Hose Hot/Closed Throttle/Park or Neutral/Closed Loop/Accessories Off/Brake Pedal Released

24X Crank Sensor

Ignition

RPM

0-6,400

A/C Relay Circuit Status

ODD

OK/Fault/Invalid State

OK

A/C Relay Circuit History

ODD

OK/Fault/Invalid State

OK

A/C Relay Command

Eng, Misfire, EGR, TAC

On/Off

Off

Air Fuel Ratio

Eng, Fuel Trim, HO2S

Ratio

14.2:1-14.7:1

APP Indicated Angle

Eng, EGR, EVAP, HO2S, Ignition, Misfire, TAC, Fuel Trim

Percent

0

APP Sensor 1

TAC

Volts

Varies

APP Sensor 1 Circuit

TAC

OK/Not OK

OK

APP Sensor 2

TAC

Volts

Varies

APP Sensor 2 Circuit

TAC

OK/Not OK

OK

APP Sensor 1

TAC

Percent

Varies

APP Sensor 2

TAC

Percent

Varies

APP Sensor 1 and 2

TAC

Agree/Disagree

Agree

BARO

Eng, EGR, EVAP, Fuel Trim, HO2S, Ignition

kPa

65-110 kPa

Catalytic Converter Protection Active

Fuel Trim, HO2S

Yes/No

No

CMP Sensor

Ignition

RPM

Varies

CMP Sensor Signal Present

Ignition, Misfire

Yes/No

Yes

Cruise Control Active

TAC

Yes/No

No

Cycles of Misfire Data

Misfire

Counts

0-99

Cyl. 1-6 Injector Circuit Status

ODD

OK/Stuck Low (open)/Stuck High

OK

Cylinder 1 and 4 IC Circuit Status

ODD

OK/Not OK

OK

Cylinder 2 and 5 IC Circuit Status

ODD

OK/Not OK

OK

Cylinder 3 and 6 IC Circuit Status

ODD

OK/Not OK

OK

Cylinder 1-6 Injector Circuit History

ODD

OK/Stuck Low (open)/Stuck High

OK

Decel Fuel Cut-off

Eng, EGR, Fuel Trim, HO2S

Active/Inactive

Inactive

Desired EGR Position

EGR, Misfire

Percent

0

Desired Idle Speed

Eng, EVAP, TAC

RPM

Varies

Driver Module 1 Status

ODD

Enabled/Off-High Volts/Off High Temp/Invalid State

Enabled

Driver Module 2 Status

ODD

Enabled/Off-High Volts/Off High Temp/Invalid State

Enabled

Driver Module 3 Status

ODD

Enabled/Off-High Volts/Off High Temp/Invalid State

Enabled

EC Ignition Relay Circuit Status

ODD

OK/Fault/Invalid State

OK

EC Relay Circuit History

ODD

OK/Fault/Invalid State

OK

ECT Sensor

Eng, EGR, EVAP, HO2S, Ignition, Misfire, Fuel Trim, TAC

°C/°F

Varies

EGR Flow Test Count

EGR

Counts

0-12

EGR Learned Minimum Position

EGR

Volts

0.14-1.0

EGR Position Sensor

Eng, EGR, Misfire

Percent

Varies

EGR Position Sensor

EGR

Volts

0

EGR Position Variance

EGR

Percent

0

EGR Solenoid Circuit History

ODD

OK/Open/Fault/Invalid State

OK

EGR Solenoid Circuit Status

ODD

OK/Fault/Invalid State

OK

EGR Solenoid Command

EGR

Percent

0

Engine Load

Eng, Misfire, Fuel Trim, EVAP, EGR, HO2S, Ignition, TAC

Percent

0

Engine Oil Pressure Switch

Eng

Low/OK

OK

Engine Run Time

Eng, EVAP, Misfire, Fuel Trim, EGR, HO2S, Ignition, TAC, ODD

Hr: Min: Sec

Varies

Engine Speed

Eng, EGR, EVAP, Ignition, Misfire, Fuel Trim, TAC

RPM

Varies

EVAP Fault History

EVAP

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

No Fault

EVAP Purge Solenoid Circuit History

ODD

OK/Open/Short

OK

EVAP Purge Solenoid Circuit Status

ODD

OK/Open/Short

OK

EVAP Purge Solenoid Command

Eng, EVAP, Fuel Trim, HO2S

Percent

Varies

EVAP Test Abort Reason

EVAP

No Aborted/Lost Enable/Small Leak/Veh. Not At Rest

Varies

EVAP Test Result

EVAP

    • No Result/Passed/Aborted
        OR
    • Fail-DTC P0455
        OR
    • Fail-DTC P0442
        OR
    • Fail-DTC P0446
        OR
    • Fail-DTC P0496

Varies

EVAP Test State

EVAP

Waiting for Purge/Test Running/Test Completed

Varies

EVAP Vent Solenoid Circuit History

ODD

OK/Open/Short

OK

EVAP Vent Solenoid Circuit Status

ODD

OK/Open/Short

OK

EVAP Vent Solenoid Command

Eng, EVAP

Venting/Not Venting

Varies

FC Relay 1 Circuit History

ODD

OK/Fault/Invalid State

OK

FC Relay 1 Circuit Status

ODD

OK/Fault/Invalid State

OK

FC Relay 2 and 3 Circuit History

ODD

OK/Fault/Invalid State

OK

FC Relay 2 and 3 Circuit Status

ODD

OK/Fault/Invalid State

OK

Fuel Level Sensor

EVAP

Volts

Varies

Fuel Pump Relay Circuit History

ODD

OK/Fault/Invalid State

OK

Fuel Pump Relay Circuit Status

ODD

OK/Fault/Invalid State

OK

Fuel Pump Relay Command

Eng

On/Off

On

Fuel Tank Level Remaining

EVAP

Percent

0-104

Fuel Tank Pressure Sensor

Eng, EVAP

mm Hg/in H2O

Varies

Fuel Tank Pressure Sensor

EVAP

Volts

Varies

Fuel Trim Cell

EVAP, Eng, Fuel Trim

0-4

0

Fuel Trim Learn

Eng, EVAP, Fuel Trim

Enabled/Disabled

Varies

HO2S Bank 1 Sensor 1

EVAP, Eng, Fuel Trim, HO2S

millivolts

0-1000 and Varying

HO2S Bank 1 Sensor 1 Ready

Fuel Trim, HO2S

Yes/No

Yes

HO2S Bank 1 Sensor 2

Eng, Fuel Trim, HO2S

millivolts

0-1000 and Varying

HO2S Bank 2 Sensor 1 Ready

Fuel Trim, HO2S

Yes/No

Yes

HO2S Bank 2 Sensor 1

Eng, EVAP, Fuel Trim, HO2S

millivolts

0-1000 and Varying

HO2S Bank 2 Sensor 2

Eng, Fuel Trim, HO2S

millivolts

0-1000 and Varying

HO2S Htr. Bn. 1 Sen. 1

HO2S

On/Off

On

HO2S Htr. Bank 1 Sensor 1 Command

HO2S

On/Off

On

HO2S Htr. Bn. 1 Sen. 2

HO2S

On/Off

On

HO2S Htr. Bank 1 Sensor 2 Command

HO2S

On/Off

On

HO2S Heater Bn. 1 Sen. 1

HO2S

Amps

Varies

HO2S Heater Bn. 1 Sen. 2

HO2S

Amps

Varies

HO2S Heater Bn. 2 Sen. 1

HO2S

Amps

Varies

HO2S Heater Bn. 2 Sen. 2

HO2S

Amps

Varies

HO2S Htr. Bn. 1 Sen. 1 Circuit History

ODD

OK/Fault/Invalid State

OK

HO2S Htr. Bn. 1 Sen. 2 Circuit History

ODD

OK/Fault/Invalid State

OK

HO2S Htr. Bn. 2 Sen. 1

HO2S

On/Off

On

HO2S Htr. Bn. 2 Sen. 1 Circuit History

ODD

OK/Fault/Invalid State

OK

HO2S Htr. Bn. 2 Sen. 2

HO2S

On/Off

On

HO2S Htr. Bn. 2 Sen. 2 Circuit History

ODD

OK/Fault/Invalid State

OK

HO2S Htr. Bn. 1 Sen. 1 Circuit Status

ODD

OK/Fault/Invalid State

OK

HO2S Htr. Bn. 1 Sen. 2 Circuit Status

ODD

OK/Fault/Invalid State

OK

HO2S Htr. Bn. 2 Sen. 1 Circuit Status

ODD

OK/Fault/Invalid State

OK

HO2S Htr. Bn. 2 Sen. 2 Circuit Status

ODD

OK/Fault/Invalid State

OK

Hot Open Loop

Fuel Trim, HO2S

Active/Inactive

Inactive

IAT Sensor

Eng, EVAP, EGR, Fuel Trim, HO2S, Ignition, Misfire, TAC

°C/°F

Varies

Ignition 1 Signal

EVAP, Eng, EGR, Fuel Trim, HO2S, Ignition, Misfire, ODD, TAC

Volts

Varies

Ignition Off Time

EVAP, Eng

Minutes/Varies

Varies

Initial Brake Apply Signal

TAC

Released/Applied

Released

Injector PWM

Fuel Trim, Misfire

milliseconds

Varies

Knock Retard

EGR, Ignition

Degrees

0

Long Term FT Bank 1

Eng, EVAP, Fuel Trim, HO2S

Percent

-10% to +10%

Long Term FT Bank 2

Eng, EVAP, Fuel Trim, HO2S

Percent

-10% to +10%

Loop Status

Eng, Fuel Trim, EVAP, HO2S

Open/Closed

Closed

MAF Sensor

Eng, EGR, Misfire, EVAP, Fuel Trim, HO2S, Ignition, TAC

g/s

3-6 (Varies with altitude)

MAF Sensor

EVAP, Fuel Trim, HO2S, Misfire, TAC

Hz

1,200-3,000 (depends on altitude)

MAP Sensor

Eng, EGR, Fuel Trim, HO2S, Misfire, TAC

Volts

0.4-2.0 Volts

MAP Sensor

Eng, EVAP, Fuel Trim, HO2S, Ignition, Misfire, EGR, TAC

kPa

20-48 kPa (Varies with altitude)

MIL Circuit History

ODD

OK/Fault/Invalid State

OK

MIL Command

EVAP, Eng, EGR, Ignition

On/Off

Off

MIL Circuit Status

ODD

OK/Fault/Invalid State

OK

Mileage Since DTC Cleared

Eng

km/h/mph

Varies

Misfire Current Cyl. 1-6

Misfire

Counts

0

Misfire History Cyl. 1-6

Misfire

Counts

0

Moderate Brake Apply Signal

TAC

Applied/Released

Released

Number of DTCs

Eng EVAP, Fuel Trim, TAC

Number

0

PCM Reset

Eng

Yes/No

No

Power Enrichment

Eng, Fuel Trim, HO2S, Misfire

Active/Inactive

Inactive

Reduced Engine Power

TAC

Active/Inactive

Inactive

Short Term FT Bank 1

Eng, EVAP, Fuel Trim, HO2S,

Percent

-10 to +10

Short Term FT Bank 2

Eng, EVAP, Fuel Trim, HO2S,

Percent

-10 to +10

Spark

Eng, Misfire, Fuel Trim, HO2S, Ignition

Degrees

22 (varies)

Start Up ECT

EVAP, Fuel Trim, HO2S

°C/°F

Varies

Start Up IAT

EVAP, Fuel Trim, HO2S

°C/°F

Varies

Starter Relay Circuit Status

ODD

OK/Fault

OK

Starter Relay Circuit History

ODD

OK/Fault/Invalid State

OK

Stop Lamp Pedal Switch

Eng, TAC

Released/Applied

Released

TAC/PCM Communications Signal

TAC

OK/Fault

OK

TAC Stop Lamp Pedal Switch

Eng

Released/Applied

Released

TAC Stop Lamp Pedal Switch

TAC

Applied/Released

Released

TAC Vehicle Speed Signal

TAC

OK/Fault

OK

TCS Delivered Torque Circuit Status

ODD

OK/Fault

OK

Torque Request Signal

TAC

Percent

100%

Torque Delivered Signal

TAC

Percent

75%

Total Misfire Count

Misfire

1-255

0

TP Desired Angle

TAC

Percent

Varies

TP Indicated Angle

Eng, EGR, Fuel Trim, HO2S, Ignition, EVAP, Misfire, TAC

Percent

%

TP Sensor 1

TAC

Percent

Varies

TP Sensor 1

TAC

Volts

Varies

TP Sensors 1 and 2

TAC

Agree/Disagree

Agree

TP Sensor 1

TAC

OK/Not OK

OK

TP Sensor 2

TAC

Percent

Varies

TP Sensor 2

TAC

Volts

Varies

TP Sensor 2

TAC

OK/Not OK

OK

Traction Control Status

TAC

Active/Inactive

Inactive

Vehicle Speed Circuit History

ODD

OK/Fault/Invalid State

OK

Vehicle Speed Circuit Status

ODD

OK/Fault/Invalid State

OK

Vehicle Speed Sensor

Eng, EGR, EVAP, HO2S, Ignition, Fuel Trim, Misfire, TAC

mph/km/h

0

Warm-ups w/o Emission Faults

Eng

1-10

0

Warm-ups w/o Non-Emission Faults

Eng

1-10

0