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/tailgate closed

Backlight Dimming

Data

Percent

Varies

Backup Lamps

Output

On/Off

Off

Backup Light Request

Input

Active/Inactive

Inactive

Battery Voltage

Data

Volts

Varies

Cargo Door Ajar Switch

Input

Open/Closed

Closed

Cargo Lamp Switch

Input

On/Off

Off

Courtesy Lamp Relay

Input

On/Off

Off

Courtesy Lamp Switch

Input

Active/Inactive

Inactive

Daytime Running Lamps

Output

Active/Inactive

Varies

Dimming Input

Data

Volts

Varies

Dimming Level

Data

Percent

0%

Dimming Potentiometer

Data

Volt

Varies

Driver Door Ajar Switch

Input

On/Off

Off

DRL Disable Switch

Input

Active/Inactive

Inactive

Flash to Pass Switch

Input

On/Off

Off

Front Fog Lamp Switch

Input

Active/Inactive

Inactive

Front Wiper Active

Input

Yes/No

No

Headlamp Switch

Input

Active/Inactive

Inactive

High Beam Relay

Output

On/Off

Off

High Beam Switch

Input

On/Off

Off

Ignition 0

Input

On/Off

On

Ignition 1

Input

On/Off

On

Ignition Accessory

Input

Active/Inactive

Active

Inadvertent Power Relay

Input

On/Off

On

Indicator Dimming

Data

Percent

Varies

Interior Lamp Defeat Switch

Input

On/Off

On/Off

Interior Lamp Output

Output

On/Off

Off

Key In Ignition

Input

Yes/No

Yes

Left Rear/Rear Cargo Door Ajar Switch

Input

On/Off

Off

Light Sensor

Data

Volts

1.75 Volts Maximum Light to 4.9 Volts Maximum Dark

Low Beam Output

Output

On/Off

Off

Man. Trans. Reverse Sw.

Input

On/Off

Off

Park Lamp Relay

Output

On/Off

On/Off

Park Lamp Switch

Input

Active/Inactive

Inactive

Passenger Door Ajar Switch

Input

On/Off

Off

Rear Fog Lamp Relay

Input

On/Off

Off

Right Rear Door Ajar Switch

Input

On/Off

Off

Engine Control Module (ECM)

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/tailgate closed

Stop Lamp Pedal Switch

Powertrain, Diesel, Data Display, Eng Data Display

Released/Applied

Released

TCC/Cruise Brake Pedal Switch

Powertrain, Diesel, Data Display, Eng Data Display

Released/Applied

Released

Driver Door Module (DDM)

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/tailgate closed

Dimming Enable

Input

On/Off

On

Dimming Potentiometer

Data

Percent

Varies

Door Ajar Switch

Input

On/Off

Off

Memory Switch Backlight

Data

Percent

Varies

Puddle Lamp Output

Output

Active/Inactive

Inactive

Window Switch Backlight

Data

Percent

Varies

Passenger Door Module (PDM)

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/tailgate closed

Backlight Dimming Enable

Output

Yes/No

Yes

Dimming Enable

Input

On/Off

On

Dimming Potentiometer

Data

Percent

Varies

Puddle Lamp Output

Output

On/Off

Off

Instrument Panel Cluster Module (IPC)

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/tailgate closed

Cargo Lamp On

Input/Output

On/Off

Off

Display Dimming

Input/Output

Percent

Varies

High Beam Lamp

Input/Output

On/Off

Off

Left Turn Input

Input/Output

Open/Closed

Open

Right Turn Input

Input/Output

Open/Closed

Open