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 Voltage

Data

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

Ignition 1 Signal

Engine Electrical

Volts

Varies

PNP Switch

Engine Electrical

Park / Neutral / In Gear

Park

Starter Relay Command

Engine Electrical

On/Off

Off

Starter Relay Circuit Status

Engine Electrical

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

OK

TR. Sw.

Transmission Data

Park / Reverse / Neutral / Drive 5 / Drive 4 / Drive 3 / Drive 2 / Drive 1

Park