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-Engine Controls 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.

Eng 1: Engine Data 1 List

Eng 2: Engine Data 2 List

Eng 3: Engine Data 3 List

EE: Enhanced EVAP Data

FF/FR: Freeze Frame/Failure Records

FT: Fuel Trim Data List

MF: Misfire Data List

TAC: Throttle Actuated Control Data List

CC: Cruise Control Data List

Scan Tool Parameter

Data List

Parameter Range/Units

Typical Data Values

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

A/C High Side Pressure Sensor

Eng 2

kPa/Volts

Varies

A/C Relay Command

Eng 1, 2, 3, MF

On/Off

Off

A/C Request Signal

Eng 2

Yes/No

No

Air Flow Calculated

Eng 1, 2, 3, EE, FT, TAC, MF

g/s

Varies

Air Fuel Ratio

Eng 2, 3, FT, FF, FR

Ratio

14.7:1

APP Average

TAC

0-100%

0%

APP Indicated Angle

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

0-100%

0%

APP Sensor 1

TAC

%/Volts

0%/1.02 Volts

APP Sensor 2

TAC

%/Volts

0%/4.04 Volts

APP Sensor 1 and 2

TAC

Agree/Disagree

Agree

BARO

Eng 1, EE, FT, FF, FR

kPa/volts

65-104 kPa/3.5-4.9 Volts Varies w/Altitude

Camshaft Actual Angle

Eng 2

Degrees

Camshaft Desired Angle

Eng 2

Degrees

Camshaft Angle Variance

Eng 2

Degrees

Camshaft Actuator Solenoid Command

Eng 2

%

0%

CKP Active Counter

Eng 2

1-250

9-250

CMP Active Counter

Eng 2

Counts

Varies

CMP Resync Counter

Eng 2

Counts

Varies

Crank Request Signal

Eng 3

Yes/No

No

Cruise Control Active

Eng 1, 3, 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 On/Off Switch

TAC, CC

On/Off

Off

Cruise Release Brake Pedal Switch

TAC

Engaged/Released

Released

Cruise Release Clutch/TCC Pedal Switches

Eng 1, 2, 3, TAC, CC

Engaged/Released

Released

Cruise Resume/Accel. Switch

TAC, CC

On/Off

Off

Cruise Set/Coast Switch

TAC, CC

On/Off

Off

Current Gear

Eng 1, 2, FF, FR, FT

0-4

1

Cycles of Misfire Data

MF

0-100 Counts

Varies

Desired Fan Speed

Eng 2, 3

RPM

Varies

Desired Idle Speed

Eng 1, 2, 3, EE, TAC, FF, FR

RPM

PCM Controlled

ECT Sensor

Eng 1, 2, 3, EE, FT, MF, FF, FR

-39° to +140°C (-38° to +284°F)

88-105°C (190-221°F) Depends on ambient temperature

Engine Load

All

0-100%

1-4% @ Idle

7-9% @ 2500 RPM

Engine Oil Level Switch

Eng 3

OK/Low

Low

Engine Oil Life Remaining

Eng 3

0-100%

Varies

Engine Oil Pressure Sensor

Eng 3

kPa/Volts

-99kPa/.02V

Engine Oil Temperature Sensor

Eng 3

°C/°F

69°C/156°F

Engine Run Time

All

Hrs, Min, Sec

Varies

Engine Speed

All

0-10,000 RPM

500-700 RPM

Engine Torque

TAC

%

0%

EVAP Purge Solenoid Command

Eng 1, EE, FT

0-100%

10-25%

EVAP Test Abort Reason

EE

Aborted/Not Aborted

Not Aborted

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, FR

Counts

Varies

Fan Speed

Eng 2, 3

RPM

PCM Controlled

Fuel Tank Pressure Sensor

Eng 1, EE

mmHg/0-5.0 volts

Varies

Fuel Trim Cell

Eng 1, EE, FT

0-23

16, 17

Fuel Level Sensor

Eng 1

0-5 volts

0.7-2.5 volts

Fuel Pump Relay Command

Eng 1

On/Off

On

Generator F Terminal Signal

Eng 2

Percent

Varies

Generator L Terminal Signal

Eng 2

Active/Inactive

Active

HO2S 1

Eng 1, EE, FT

(mV

10-1,000 mV and Varying

HO2S 2

Eng 1, FT

(mV)

10-1,000 mV and Varying

HO2S 1 Heater Command

FT

On/Off

On

HO2S 2 Heater Command

FT

On/Off

On

IAT Sensor

Eng 1, 2, 3, EE, FT

-39 to +140°C (-38 to +284°F)

35°C (91°F) Depends on ambient temperature

Ignition 1 Signal

Eng 1, 2, 3, EE, FT, TAC, CC

0-25 volts

11.5-14.5 Volts

Injector PWM

Eng 2, FT, FF, FR, MF

Milliseconds

2-6 ms

Injector 1 Command

Eng 3

Milliseconds

2.49-2.59 ms

Injector 2 Command

Eng 3

Milliseconds

2.49-2.59 ms

Injector 3 Command

Eng 3

Milliseconds

2.49-2.59 ms

Injector 4 Command

Eng 3

Milliseconds

2.49-2.59 ms

Injector 5 Command

Eng 3

Milliseconds

2.49-2.59 ms

Injector 6 Command

Eng 3

Milliseconds

2.49-2.59 ms

Knock Retard

Eng 1

0°-16°

Knock Sensor 1

Eng 1

Volts

0.8-0.9V

Knock Sensor 2

Eng 1

Volts

0.9-1.0V

Long Term FT

Eng 1, 2, 3, EE, FT

Percentage

Near 0%

Loop Status

Eng 1, 2, 3, EE, FT, FF, FR

Open/Closed

Closed

MAP Sensor

Eng 1, 2, 3, EE, FT, TAC, MF

kPa

20-48 kPa

MAP Sensor

Eng 1, 2, 3

Volts

1.0-2.0 volts Varies with altitude

Medium Resolution Resync Counter

Eng 2

Counts

0

MIL Command

Eng 1

Off/On

Off

Misfire Current Cyl #1

MF

Varies

0

Misfire Current Cyl #2

MF

Varies

0

Misfire Current Cyl #3

MF

Varies

0

Misfire Current Cyl #4

MF

Varies

0

Misfire Current Cyl #5

MF

Varies

0

Misfire Current Cyl #6

MF

Varies

0

Misfire History Cyl #1

MF

Varies

0

Misfire History Cyl #2

MF

Varies

0

Misfire History Cyl #3

MF

Varies

0

Misfire History Cyl #4

MF

Varies

0

Misfire History Cyl #5

MF

Varies

0

Misfire History Cyl #6

MF

Varies

0

Number of DTC(s)

Eng 1, EE, FT, TAC

Varies

0

PCM in VTD Fail Enable

Eng 3

Yes/No

No

Power Enrichment

Eng 2, FT, MF

Yes/No

No

Reduced Engine Power

Eng 1, 3, TAC, CC

Yes/No

No

Reference Voltage 1 Signal

TAC

Volts

4.57V

Reference Voltage 2 Signal

TAC

Volts

4.57V

Short Term FT

Eng 1, 2, 3, EE, FT

Percentage

Near 0%

Spark

Eng 1, 2, 3, FT, MF

Degrees

15°-20°

Start Up ECT

Eng 2, FT, FF, FR

°C/°F

Varies

Starter Relay Command

Eng 3

On/Off

Off

TCC Enable Solenoid Command

Eng 1, 2, MF, CC, FF, FR

Enabled/Disabled

Disabled

Torque Delivered Signal

TAC

N-M/ft-lbs

0 N-M/ft-lbs

Torque Request Signal

TAC

%

0%

TP Desired Angle

Eng 1, 2, EE, TAC

Percentage

4.2%

TP Indicated Angle

Eng 1, 2, 3, EE, FT, TAC, MF, CC

Percentage

4.2%

TP Sensors 1 and 2

TAC

Agree/Disagree

Agree

TP Sensor 1

TAC, FF, FR

0-100%

0%

TP Sensor 2

TAC, FF, FR

0-100%

0%

TP Sensor 1

TAC, FF, FR

0-5.0 volts

4.24 volts

TP Sensor 2

TAC, FF, FR

0-5.0 volts

.78 volts

Traction Control Signal

TAC, CC

Active/Inactive

Inactive

TR Switch

Eng 2, 3, FT, CC

Transmission Gear Position

Varies

TWC Temperature Calculated

FT

Degrees

450°C

Vehicle Speed Sensor

All

km/h

mph

0

VTD Fuel Disable

Eng 3

Active/Inactive

Inactive

VTD Password

Eng 3

Fault/Ok

Ok

VTD Auto. Learn Timer

Eng 3

Active/Inactive

Inactive

VTD Fuel Disable Until Ignition Off

Eng 3

Yes/No

No