GM Service Manual Online
For 1990-2009 cars only

Body Control Module (BCM)

Scan Tool Parameter

Data List

Units Displayed

Typical Data Value

Ignition ON/Engine Running

Battery Low at Start

Data Display/ Charging Info

Yes/No

No

Batt. Open Ckt. Tested

Data Display/ Charging Info

Yes/No

No

Batt. Open Ckt. Voltage

Data Display/ Charging Info

Volts

13.03 Volts

Battery Voltage

Data Display/ Charging Info

Volts

13.9 Volts

Batt. Voltage High Res.

Data Display/ Charging Info

Volts

12.417 Volts

Parasitic Current

Data Display/ Charging Info

Amps

0.0 Amps

Prev. State of Charge

Data Display/ Charging Info

%

90%

Start Up State of Charge

Data Display/ Charging Info

%

80%

State of Charge

Data Display/ Charging Info

%

85%

State of Charge Low

Data Display/ Charging Info

Yes/No

No

Digital Radio Receiver (DRR)

Scan Tool Parameter

Data List

Units Displayed

Typical Data Value

Ignition ON/Engine Running

Battery Voltage

Data Display

Volts

13.9 Volts

Engine Control Module (ECM)

Scan Tool Parameter

Data List

Units Displayed

Typical Data Value

Ignition ON/Engine OFF

Crank Request Signal

Electrical/Theft Data

Yes/No

No

GEN F-Terminal Signal

Electrical/Theft Data

%

0%

GEN L-Terminal Signal Command

Electrical/Theft Data

ON / OFF

OFF

GEN L-Terminal Circuit Status

Electrical/Theft Data

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

OK

Ignition 1 Signal

Electrical/Theft Data

Volts

Varies

PNP Switch

Electrical/Theft Data

Park/Neutral/In Gear

Park

    

Starter Relay Command

Electrical/Theft Data

On/Off

Off

Starter Relay Circuit Status

Electrical/Theft Data

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

OK

Instrument Panel Cluster (IPC)

Scan Tool Parameter

Data List

Units Displayed

Typical Data Value

Ignition ON/Engine Running

Battery Voltage

Data Display

Volts

13.9 Volts

Vehicle Theft Deterrent (VTD)

Scan Tool Parameter

Data List

Units Displayed

Typical Data Value

Ignition ON

Ignition Voltage Signal

Data Display

Present / Not Present

Present

Start Disabled

Data Display

Yes/No

No

Sensing Diagnostic Module (SDM)

Scan Tool Parameter

Data List

Units Displayed

Typical Data Value

Ignition ON/Engine Running

Battery Voltage Signal

Data Display

Volts

13.9 Volts

Transmission Control Module (TCM)

Scan Tool Parameter

Data List

Units Displayed

Typical Data Value

Ignition ON/Transmission in Park

IMS

Engine Electrical

Park, Park/Reverse, Reverse, Reverse/Neutral, Neutral, Neutral/Drive 4, Drive 4, Drive 4/Drive 3, Drive 3, Drive 3/Drive 2, Drive 2, Drive 2/Drive 1, Drive 1, INVALID, OPEN

Park