GM Service Manual Online
For 1990-2009 cars only

The Engine Electrical Scan Tool Data List contains all engine electrical 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 Electrical 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.

Scan tool values from a properly running engine may be used for comparison with the engine you are diagnosing. The Engine Electrical 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 Electrical 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.

Body: Body, BCM Data List

Cooling/HVAC: Cooling/HVAC Data List

Cruise/Traction: Cruise/Traction Data List

Eng: Engine Data List

Electrical/Theft: Electrical/Theft Data List

EE: Enhanced Evaporative Emission (EVAP) Data

FT: Fuel Trim Data List

H2: Heated Oxygen Sensor (HO2S) Data List

IG: Ignition System Data List

IPC: IPC Data List

MT: Manual Transmission Data List

MF: Misfire Data List

OD: Output Driver Data List

TAC: Throttle Actuator Control (TAC) 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

Alternator Input Signal

BCM, IPC

On/Off

On

Battery Voltage

Body, IPC

Volts

B+

Clutch Start Switch (If Equipped)

Electrical/Theft, MT

Applied/Released

Applied

CPP Switch (If Equipped)

Cruise/Traction, MT, TAC

Applied/Released

Applied

Current Gear

IPC

Transmission Gear Position

Varies

5-Volt Reference 1

Cooling/HVAC, Eng, EE, IG, TAC

Volts

4.5 Volts

5-Volt Reference 2

Cooling/HVAC, Eng, EE, IG, TAC

Volts

4.5 Volts

GEN L-Terminal Signal Command

Electrical/Theft

Off/On

Off

GEN L-Terminal Signal

Electrical/Theft

%

0-100%

Ignition 1 Signal

All

0-25 Volts

11.5-14.5 Volts

PNP Switch (If Equipped)

Electrical/Theft

Park/Neutral

Park/Neutral

Reverse Inhibit Solenoid Command

MT

Off/On

Off

Reverse Inhibit Solenoid Circuit Status

MT

OK, Incomplete, Short B+, Short Gnd/Open

OK

Starter Relay Circuit Status

Electrical/Theft, OD

OK, Incomplete, Short B+, Short Gnd/Open

OK

Starter Relay Command

Cruise/Traction, Electrical/Theft

Off/On

Off

TCC/Cruise Brake Pedal Switch

MT, TAC

Applied/Released

Release

TR Sw

Eng 2, EGR, FT

Transmission Gear Position

Varies