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/Vehicle in PARK/Park Brake RELEASED/Headlamps in AUTO/All doors closed

Accessory Switch

Input

Active/Inactive

Inactive

Backup Lamps

Output

On/Off

Off

Battery Voltage

Data

Volts

Varies

Cargo Door Ajar Switch

Input

Open/Closed

Closed

Courtesy Lamp Switch

Input

On/Off

Off

Daytime Running Lamps

Output

Active/Inactive

Inactive

Dimming Potentiometer

Data

Volts

Varies

Dimming Potentiometer R

Data

Volts

5.0

Driver Door Ajar Sw.

Input

On/Off

Off

Flash to Pass Switch

Input

On/Off

Off

Headlamps On Indicator

Output

On/Off

Off

Headlamp Switch

Input

Active/Inactive

Inactive

High Beam Relay

Output

On/Off

Off

High Beam Switch

Input

On/Off

Off

Ignition Unlock

Input

Active/Inactive

Active

Inadvertent Power

Output

On/Off

On

Interior Lamp Defeat Switch

Input

Active/Inactive

Inactive

Key In Ignition

Input

Yes/No

Yes

Park Brake Switch

Input

Set/Released

Released

Park Lamp Relay

Output

On/Off

On/Off

Park Lamp Switch

Input

Active/Inactive

Inactive

RAP Relay

Output

On/Off

On

Passenger/Rear Cargo Do

Input

On/Off

Off

Run/Crank

Input

Active/Inactive

Inactive