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

12.6 Volts

Regulated Voltage Control Current Sensor

Data

Percent

40 Percent

Starter Switch

Inputs

Cranking/Released

Cranking

Engine Control Module (ECM)

Scan Tool Parameter

Data List

Units Displayed

Typical Data Value

Ignition ON/Engine OFF/Transmission in Park

Crank Request Signal

ECM Data List

Yes/No

No

GEN F-Terminal Signal

ECM Data List

Percent

20 Percent

GEN L-Terminal Signal Command

ECM Data Display

On/Off

Off

Ignition 1 Signal

ECM Data Display

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

PNP Switch

ECM Data Display

Park/Neutral, In Gear

Park/Neutral

Starter Relay Circuit Status

ECM Data Display

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

OK

Starter Relay Command

ECM Data Display

On/Off

Off

Powertrain Control Module (PCM)

Scan Tool Parameter

Data List

Units Displayed

Typical Data Value

Ignition ON/Engine OFF/Transmission in Park

Crank Request Signal

PCM Data List

Yes/No

No

GEN F-Terminal Signal

PCM Data List

Percent

20 Percent

GEN L-Terminal Signal Command

PCM Data Display

On/Off

Off

Ignition 1 Signal

PCM Data Display

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

PCM Data Display

Open, Short, Invalid, OK

OK

Starter Relay Command

PCM Data Display

On/Off

Off