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 Engine Controls Diagnostic System Check 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 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 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 1: Engine Data 1

Eng 2: Engine Data 2

EGR: EGR Data

EVAP: EVAP Data

FUEL TRIM: Fuel Trim Data

Misfire: Misfire Data

ODD: Output Driver 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

3X Crank sensor

Eng 2

RPM

Varies

18X Crank sensor

Eng 2

RPM

Varies

1-2 Solenoid Circuit Status

ODD

OK/Fault/Invalid State

OK

2-3 Solenoid Circuit Status

ODD

OK/Fault/Invalid State

OK

A/C High Side Pressure Sensor

Eng 2

kPa/Volts/PSI

Varies

A/C Off For WOT

Eng 2

Yes/No

No

A/C Pressure Disable

Eng 2

Yes/No

No

A/C Relay Circuit Status

ODD

OK/Fault/Invalid State

OK

A/C Relay Command

Eng 1, 2, Misfire, EGR

On/Off

Off

A/C Request Signal

Eng 2

Yes/No

No

Air Fuel Ratio

Eng 2, Fuel Trim

Ratio

14.2:1 - 14.7:1

AIR Pump Relay Circuit Status

ODD

OK/Stuck Low (open)/Stuck High/Fault

OK

AIR Pump Relay Command

Eng 1, Fuel Trim

ON/OFF

OFF

AIR Solenoid Circuit Status

ODD

OK/Stuck Low (open)/Stuck High/Fault

OK

AIR Solenoid Command

Eng 1, Fuel Trim

ON/OFF

OFF

BARO

Eng 1, EGR, EVAP, Fuel Trim

kPa

65-110 kPa

CMP Sensor Signal Present

Eng 2

Yes/No

Yes

Cruise Control Active

Eng 1

Yes/No

No

Cruise Inhibit Reason

Eng 1

Vehicle Speed/ Brake/Clutch

Vehicle Speed

Cruise Inhibit Signal Circuit Status

ODD

OK/Stuck Low (open)/Stuck High/Fault

OK

Cruise Inhibit Signal Command

Eng 1

On/Off

On

Current Gear

Eng 1, Eng 2, EGR, Fuel Trim

Transmission Gear Position

1

Cycles of Misfire Data

Misfire

Counts

0-99

Cyl. 1-6 Injector Circuit History

ODD

OK

OK

Cyl. 1-6 Injector Circuit Status

ODD

OK/Stuck Low (open)/Stuck High

OK

Decel Fuel Cutoff

EGR, Fuel Trim

Active/Inactive

Inactive

Desired EGR Position

Eng 1, EGR, Misfire

Percent

0

Desired EGR Position

EGR

Volts

0

Desired Idle Speed

Eng 1, 2, EVAP

RPM

PCM Controlled (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

Driver Module 4 Status

ODD

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

Enabled

ECT Sensor

Eng 1, 2, EGR, EVAP, Misfire, Fuel Trim

°C/°F

Varies

EGR Flow Test Count

EGR

Counts

0-12

EGR Learned Minimum Position

EGR

Volts

0.14-1.0

EGR Position Sensor

Engine 1, EGR, Misfire

Percent

Varies

EGR Position Sensor

EGR

Volts

0

EGR Position Variance

EGR

Percent

0

EGR Solenoid Circuit History

ODD

OK/Fault/ Invalid State

OK

EGR Solenoid Circuit Status

ODD

OK/Fault/ Invalid State

OK

EGR Solenoid Command

EGR

Percent

0

Engine Load

Eng 1, 2, Misfire, Fuel Trim, EVAP, EGR

Percent

0-100 (Varies)

Engine Oil Level Switch

Eng 2

OK/Low

OK

Engine Oil Life Remaining

Eng 2

Percent

0-100% (Varies)

Engine Oil Pressure Switch

Eng 2

OK/Low

OK

Engine Run Time

Engine 1, 2, EVAP, Misfire, Fuel Trim, EGR

Hr: Min: Sec

Varies

Engine Speed

Eng 1, 2, EGR, EVAP, Misfire, Fuel Trim

RPM

Varies

EVAP Fault History

EVAP

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

No Fault

EVAP Purge Solenoid Circuit Status

ODD

OK/Fault/Invalid State

OK

EVAP Purge Solenoid Command

Eng 1, EVAP, Fuel Trim

Percent

Varies

EVAP Test Abort Reason

EVAP

Not Aborted/Lost Enable/Small Leak/Vehicle Not At Rest

Not Aborted

EVAP Test Result

EVAP

No Result/Passed/Aborted/Fail DTCXXXX

Passed

EVAP Test State

EVAP

Wait For Purge/Test Running/Test Completed

Test Completed

EVAP Vent Solenoid Circuit Status

ODD

OK/Fault/Invalid State

OK

EVAP Vent Solenoid Command

Engine 1, EVAP, Fuel Trim

Venting/Not Venting

Varies

FC Relay 1 Circuit Status

ODD

OK/Fault/Invalid State

OK

FC Relay 1 Command

Eng 2

On/Off

Off

FC Relay 2 and 3 Circuit Status

ODD

OK/Fault/Invalid State

OK

FC Relay 2 and 3 Command

Eng 2

On/Off

Off

Fuel Pump Relay Circuit History Status

ODD

OK/Fault/Invalid State

OK

Fuel Pump Relay Circuit Status

ODD

OK/Fault/Invalid State

OK

Fuel Pump Relay Command

Eng 1

On/Off

On

Fuel Tank Level Remaining

EVAP

Percent

0-100

Fuel Tank Pressure Sensor

Engine 1, EVAP

mm Hg/in H2O

Varies

Fuel Tank Pressure Sensor

EVAP

Volts

Varies

Fuel Trim Cell

EVAP, Eng 1, Fuel Trim

0-4

0

Fuel Trim Learn

Eng 1, EVAP, Fuel Trim

Enabled/Disabled

Varies

GEN L-Terminal Signal Command

Eng 2

On/Off

On

HO2S 1

EVAP, Eng 1, Fuel Trim

millivolts

0-1000 and Varying

HO2S 2

Eng 1, Fuel Trim

millivolts

0-1000 and Varying

IAC Position

Eng 1, EGR, Fuel Trim

Counts

10-60

IAT Sensor

Eng 1, 2, EVAP, EGR, Fuel Trim

°C/°F

Varies

Ignition 1 Signal

EVAP, Eng 1, 2, EGR, Fuel Trim

Volts

Varies

Ignition Mode

Eng 2

IC/Bypass

IC

Injector PWM

Eng 2, Fuel Trim, Misfire

milliseconds

Varies (1.5-3.5)

Knock Retard

Eng 1, EGR

Degrees

0

Long Term FT

Eng 1, 2, EVAP, Fuel Trim

Percent

-10% to +10%

Loop Status

Eng 1, 2, fuel Trim, EVAP, EGR

Open/Closed

Closed

MAF Sensor

Eng 1, 2, EGR, Misfire, EVAP, Fuel Trim

g/s

3-6 (depends on altitude)

MAF Sensor

Eng 2

Hz

1200-3000 (depends on altitude)

MAP Sensor

Eng 1, 2

Volts

0.4-2.0 Volts

MAP Sensor

Eng 1, 2, EVAP, Fuel Trim, Misfire, EGR

kPa

20-48 kPa (depends on altitude)

MIL Circuit Status

ODD

OK/Fault/Invalid State

OK

MIL Command

Eng 2

On/Off

Off

Misfire Current Cyl. 1-6

Misfire

Counts

0-4

Misfire History Cyl. 1-6

Misfire

Counts

0

Number of DTCs

Eng 1, EVAP, Fuel Trim

#

0

PCM/VCM in VTD Fail Enable

Eng 1

Yes/No

Yes

Power Enrichment

Eng 2, Misfire

Active/Inactive

Inactive

Short Term FT

Eng 1, 2, EVAP, Fuel Trim

Percent

-10% to +10%

Spark

Eng 1, 2, Misfire, Fuel Trim

Degrees

22 (varies)

Starter Enable Relay Circuit Status

ODD

OK/Fault/Invalid State

OK

Starter Relay Command

Eng 2

On/Off

Off

Start Up ECT

EVAP, Fuel Trim

°C/°F

Varies

Start Up IAT

EVAP, Fuel Trim

°C/°F

Varies

TCC Brake Pedal Switch

Eng 1, 2

Applied/Released

Released

TCC PWM Solenoid Command

Eng 2

On/Off

Off

TCS Circuit Status

ODD

OK/Fault/Invalid State

OK

TCS Circuit History

ODD

OK/Fault/Invalid State

OK

TFP Sw.

Eng 2, EGR, Fuel Trim

Park/Neutral/Drive 1/Drive 2/Drive 3/Drive 4

Park/Neutral

TP Sensor

Eng 1, 2, EGR, Fuel Trim, EVAP, Misfire

Percent

0

TP Sensor

Eng 1, 2

Volts

0.2-0.8

Traction Control Status (IF Equipped)

Eng 2

Active/Inactive

Inactive

Torque Delivered Signal (IF Equipped)

Eng 2

Percent

85%

Torque Request Signal (IF Equipped)

Eng 2

Percent

100%

Vehicle Speed Sensor

Eng 1, 2, EGR, EVAP, Fuel Trim, Misfire

MPH/Km/h

0

VTD Auto. Learn Timer

Eng 1

Active/Inactive

Inactive

VTD Fuel Disable

Eng 1

Active/Inactive

Inactive

VTD Fuel Disable Until Ign. OFF

Eng 1

Yes/No

No