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 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 the values that would be seen on a normal running 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 can result in misdiagnosis and in 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 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:

CMP: CMP Actuator Data List

Eng 1: Engine Data 1 List

EVAP: EVAP Data

FT: Fuel Trim Data List

HO2S: HO2S Data List

Ign: Ignition Data List

MF: Misfire Data List

ODM: Output Driver Data List

TAC: TAC Data List

Scan Tool Parameter

Data List

Parameter Range/Units

Typical Data Values

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

A/C Relay Circuit Status

ODM

OK/Fault

OK

A/C Relay Command

Eng 1, MF

On/Off

Off

APP Indicated Angle

CMP, EVAP, HO2S, Ign, TAC, FT

0-99%

0 percent at idle

APP Sensor 1

TAC

0.9-4.5 Volts

1 Volt

APP Sensor 1

TAC

%

2%

APP Sensor 2

TAC

0.45-2.25 Volts

0.5 Volt

APP Sensor 2

TAC

%

2%

APP Sensor 1 and 2

TAC

Agree/Disagree

Agree

Baro

Eng 1, EVAP, FT, HO2S, Ign

65-104 kPa -16 psi

Varies with altitude

Catalytic Converter Protection Active

FT, HO2S

Yes/No

No

Commanded Gear

Eng 1, FT, MF

P/N/R/1-5

P/N

Cruise Control Active

Eng 1, TAC

Active/Inactive

Inactive

Current Gear Signal

Eng 1, FT

Valid/Invalid

Valid

Cycles of Misfire Data

MF

0-9999

0

Cylinder 1-8 IC Circuit Status

ODM

Fault/OK

OK

Cylinder 1-8 Injector Circuit Status

ODM

Fault/OK

OK

Cylinder 1-8 Knock Retard

Ign

Degrees

0

Decel. Fuel Cutoff

Eng 1, FT, HO2S

Active/Inactive

Inactive

Desired Exhaust CMP Bn 1 or Bn 2

CMP

Degrees

0

Desired HO2S Bank 1 or Bank 2 Sensor 1

FT, HO2S

Lambda

Varies

Desired Idle Speed

CMP, Eng 1, EVAP, TAC

0-7,000 RPM

650 RPM

Desired Intake CMP Bn 1 or Bn 2

CMP

Degrees

0

Desired Ignition Spark

Ign

0-100%

68%

Desired Torque

Ign, FT

N·m

45-55

EC Ignition Relay Command

Eng 1, TAC

On/Off

On

EC Ignition Relay Feedback Signal

Eng 1, TAC

volts

13.5 V

ECM Reset

Eng 1, EVAP, FT, Ign, ODM,

Yes/NO

No

ECT Sensor

CMP, Eng 1, EVAP, FT, Ign 1, HO2S, MF, TAC

-39 to +140°C/-38 to +284°F

85-105°C/185-220°F

Engine Load

CMP, Eng 1, EVAP, FT, HO2S, Ign, MF, TAC

0-99%

2%

Engine Off EVAP Test Conditions Met

EVAP

Yes/No

No

Engine Off EVAP Test Ran Last Ignition Cycle

EVAP

Yes/No

No

Engine Off Time

EVAP

Seconds

0

Engine Oil Level Switch

Eng 1, CMP

OK/Low

OK

Engine Oil Life Remaining

CMP

%

Varies

Engine Oil Pressure Sensor

CMP, Eng1, MF

kPa

180 kPa

Engine Oil Temperature

CMP

°C/°F

95°C

Engine Run Time

CMP, Eng 1, EVAP, FT, HO2S, Ign, MF, TAC

0:00:00

Varies

Engine Speed

CMP, Eng 1, EVAP, FT, HO2S, Ign, MF, TAC

RPM

650 RPM

Engine Torque

Ign, FT

N·m

45-55

EVAP Fault History

EVAP

Fault/No Fault

No Fault

EVAP Purge Solenoid Command

Eng 1, EVAP, FT, HO2S

0-100%

Varies

EVAP Purge Solenoid Circuit Status

ODM

Fault/OK

OK

EVAP Vent Solenoid Command

Eng 1, EVAP, FT

On/Off

Off

EVAP Vent Solenoid Circuit Status

ODM

Fault/OK

OK

EVAP Test Abort Reason

EVAP

Aborted/Not Aborted

Not Aborted

EVAP Test Result

EVAP

No Result

No Result

EVAP Test State

EVAP

Purge/wait for purge

Wait for purge

Exh. CMP Angle Bank 1 or Bank 2

CMP, Eng 1, Ign

Degrees

0

FC Relay 1 Circuit Status

ODM

Fault/OK

OK

FC Relay 2 Circuit Status

ODM

Fault/OK

OK

FC Relay 1 Command

Eng 1

ON/OFF

ON

FC Relay 2 Command

Eng 1

ON/OFF

ON

Fuel Level Sensor Left Tank

EVAP

0-5 Volts

Varies

Fuel Level Sensor Right Tank

EVAP

0-5 Volts

Varies

Fuel Pump Command

Eng 1

On/Off

On

Fuel Pump Relay Circuit Status

ODM

Fault/OK

OK

Fuel Tank Level Remaining

Eng 1, EVAP , MF

Gal/L

Varies

Fuel Tank Pressure

EVAP

Volts

0-5 Volts

Fuel Tank Pressure Sensor

Eng 1, EVAP

in H2O/mm Hg

Varies

Fuel Tank Rated Capacity

EVAP

Liters/Gal

Varies

Fuel Trim Cell

Eng 1, EVAP, FT

Varies

2

Fuel Trim Learn

Eng 1, EVAP, FT

Enabled/Disabled

Enabled

Fuel Volatility

EVAP, FT

Low/High

Low

Gen L Terminal Signal Command

Eng 1

On/Off

On

HO2S Bank 1 or Bank 2 Sensor 1

Eng 1, EVAP, FT, HO2S

Lambda

Varies

HO2S Bank 1 or Bank 2 Sensor 2

Eng 1, FT, HO2S

0-4,998 mV

Varies 400-800 mV

HO2S Heater Bn. 1 or Bn. 2 Sen. 1

FT, HO2S

0-99%

Varies

HO2S Heater Bn. 1 or Bn. 2 Sen. 2

FT, HO2S

0-99%

Varies

Hot Open Loop

HO2S, FT

Active/Inactive

Inactive

IAT Sensor

CMP, Eng 1, EVAP, FT, HO2S, Ign, TAC

-39 to +140°C/-38 to +284°F

Varies

Ignition 0 Signal

Eng 1, TAC

ON/OFF

ON

Ignition 1 Signal

CMP, Eng 1, EVAP, FT, HO2S, Ign, MF, TAC

0-25.5 Volts

12.8-14.2 Volts

Ignition Spark Efficiency

Ign

0-100%

Varies

Initial Brake Apply Signal

Eng 1, TAC

Applied/Released

Released

Injector Bn. 1 or Bn. 2 PWM Average

Eng 1, FT, HO2S, Ign, MF

0-9 ms

3.0-5.4 ms

Injector 1-8 Command

FT, MF

mS

Varies

Instant FT Bank 1 or Bank 2

FT

%

Varies

Int CMP Angle Bank 1 or Bank 2 Signal

Eng 1, Ign

Degrees

0

Int CMP angle Bank 1 or Bank 2 Command

CMP

0-100%

7%

Integral FT Bank 1 or Bank 2

FT

%

Varies

Knock Retard

Eng1, Ign

0-191 Degrees

0

Long Term FT Bank 1 or Bank. 2

Eng 1, EVAP, FT, HO2S

-100 to +100%

9%

LT FT High RPM/Load Bn. 1 or Bn. 2

FT

-100 to +100%

-50%

LT FT Low RPM/Load Bn. 1 or Bn. 2

FT

mg

255

Loop Status

Eng 1, EVAP, FT, HO2S

Open/Closed

Closed

MAF Sensor

CMP, Eng 1, EVAP, HO2S, Ign, MF, TAC, FT

0-655 g/s

3-7 g/s

MAF Sensor

CMP, Eng 1, EVAP, HO2S, MF, TAC

0-9999 Hz

28 Hz

MAP Sensor

CMP, Eng 1, EVAP, FT, HO2S, Ign, MF, TAC, FT

kPa/psi

33

MIL Circuit Status

ODM

Fault/OK

OK

MIL Command

Eng 1, Ign

On/Off

Off

MIL Requested by DTC

Eng 1, Ign

Yes/No

No

Mileage Since DTC Cleared

Eng 1

km/mi

Varies

Misfire Detects Rough Road

MF

Yes/No

No

Misfire History Cyl. 1-8

MF

0-255 Counts

0

Moderate Brake Apply Signal

Eng 1, TAC,

Applied/Released

Released

PNP Switch

Eng 1

In Gear/Park/Neutral

Park/Neutral

Power Enrichment

Eng 1, FT, HO2S, MF

Active/Inactive

Inactive

Reduced Engine Power

Eng 1, TAC

Active/Inactive

Inactive

Reference Voltage 1 Signal

Eng 1, Ign, TAC

0-5 Volts

5 V

Reference Voltage 2 Signal

Eng 1, Ign, TAC

0-5 Volts

5 V

Short Term FT Bank 1 or Bank 2

Eng 1, EVAP, FT, HO2S

-100 to +100%

-3% to +3%

Spark

Eng 1, FT, HO2S, Ign, MF

-133 to +78 Degrees

2-5 Degrees

Start Up ECT

EVAP, FT, HO2S

-39 to +140°C/-38 to +284°F

Varies

Start Up IAT

EVAP, FT, HO2S

-39 to +140°C/-38 to +284°F

Varies

Starter Relay Circuit Status

ODM

OK/Fault

OK

Starter Relay Command

Eng 1

On/Off

Off

Stoplamp Pedal Switch

Eng 1, TAC

Applied/Released

Released

TAC Motor Command

TAC

%

12-26%

TAC Direction

TAC

Closed/Open

Closed

TCS Control Signal

TAC

None/Reduced

None

Torque Request Signal

TAC

Valid/Invalid

Valid

Total Misfire Count

MF

0-9999

0

TP Sensor 1 Learned Min

TAC

0-5 Volts

0-0.5 Volts

TP Sensor 2 Learned Min

TAC

5-0 Volts

5-3.7 Volts

TP Desired Angle

Eng 1, EVAP, TAC

0-99%

Varies

TP Indicated Angle

CMP, Eng 1, EVAP, FT, HO2S, Ign, MF, TAC

0-99%

2 percent

TP Learned

TAC

Yes/No

No

TP Learn Enables

TAC

Yes/No

No

TP Learn Required

TAC

Yes/No

No

TP Sensor 1

TAC

0-5 Volts

0.5-0.8 Volts

TP Sensor 1

TAC

%

1

TP Sensors 1 and 2

TAC

Agree/Disagree

Agree

TP Sensor 2

TAC

0-5 Volts

4.1-4.5 Volts

TP Sensor 2

TAC

%

1

Transmission Gear Selector Signal

Eng 1

Valid/Invalid

Valid

TWC Temperature Calculated

FT, MF

C/F

Varies

Vehicle Security Status

Eng 1

Fuel Continue/Fuel Disable

Fuel Continue

Vehicle Speed Sensor

CMP, Eng 1, EVAP, FT, HO2S, Ign, MF, TAC

km/mi

0

VTD Password Learn Enabled

Eng 1

Yes/No

No