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 OFF

Battery Voltage

Data

Volts

12.6 Volts

Regulated Voltage Control Current Sensor

Data

%

Varies

Starter Switch

Inputs

Cranking

Released

Engine Control Module (ECM)

Scan Tool Parameter

Data List

Units Displayed

Typical Data Value

Ignition ON/Engine OFF/Transmission in Park

GEN F-Terminal Signal

Engine Electrical

%

Varies

GEN L-Terminal Signal Command

Engine Electrical

%

Varies

GEN L-Terminal Status

Engine Electrical

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

OK

Ignition 1 Signal

Engine Electrical

Volts

12.6 Volts

PNP Switch

Engine Electrical

In Gear/Park/Neutral

Park/Neutral

RVS Request Signal

Engine Electrical

On/Off

Off

Starter Relay Circuit Status

Engine Electrical

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

OK

Starter Relay Command

Engine Electrical

On/Off

On

Instrument Panel Cluster (IPC)

Scan Tool Parameter

Data List

Units Displayed

Typical Data Value

Ignition ON/Engine OFF

Battery Voltage

Data

Volts

12.6 Volts

Powertrain Control Module (PCM)

Scan Tool Parameter

Data List

Units Displayed

Typical Data Value

Ignition ON/Engine OFF/Transmission in Park

Crank Request Signal

Engine Electrical

Yes/No

No

GEN F-Terminal Signal Command

Engine Electrical

%

Varies

GEN L-Terminal Signal

Engine Electrical

On/Off

Off

Ignition 1 Signal

Engine Electrical

Volts

12.6 Volts

IMS

Transmission Data

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

Starter Relay Circuit History

Engine Electrical

OK/Fault/Invalid State

OK

Starter Relay Command

Engine Electrical

On/Off

Off

Transmission Control Module (TCM)

Scan Tool Parameter

Data List

Units Displayed

Typical Data Value

Ignition ON/Engine OFF/Transmission in Park

IMS

Transmission Data

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