GM Service Manual Online
For 1990-2009 cars only

Body Control Module (BCM)

The body control module (BCM) controls the automatic door locks.

Diagnostic Trouble Codes (DTCs)

The BCM may set the following DTCs in relation to the automatic door locks:

    •  DTC B3069 RF/LF Door Key Unlock Circuit Low
    •  DTC B3137 All Door Lock Circuit Low
    •  DTC B3138 All Door Lock Circuit High
    •  DTC B3132 All Door Unlock Circuit Low
    •  DTC B3133 All Door Unlock Circuit High
    •  DTC B3128 LF Door Only Unlock Circuit High
    •  DTC B3127 LF Door Only Unlock Circuit Low
    •  DTC B3272 RF/LF Door Lock/Unlock Switch CKT Low

Refer to Diagnostic Trouble Code (DTC) List/Type in Body Control System.

Door Lock Features

The BCM has the following automatic door lock features:

All door unlock: The BCM unlocks all of the doors when you press UNLOCK on either door lock switch.

All door lock: The BCM locks all of the doors when you press LOCK on either door lock switch.

Last door closed locking: The BCM locks all of the doors 5 seconds after the vehicle doors are closed. This feature occurs if the ignition switch is in the LOCK position and the key is removed from the ignition and you press LOCK on either door lock switch.

Lockout prevention: The BCM does not lock the doors when you press LOCK on either door lock switch if the key is in the ignition cylinder and the driver door is open.

Lockout prevention override: The BCM overrides the lockout prevention and locks all of the doors. This feature occurs when you press and hold LOCK on either door lock switch for at least 3 seconds.

Shift into PARK unlock: The BCM unlocks all of the vehicle doors when the transaxle is shifted into PARK.

Shift out of PARK lock: The BCM locks all of the vehicle doors when you shift the transaxle out of PARK, the vehicle reaches 13 mph and all the doors are closed.

Automatic door lock relock: The BCM locks the doors when all of the doors are closed, the ignition switch is in RUN and the transaxle is out of PARK.

Remote driver door unlock: The BCM unlocks the driver door when you press UNLOCK on the keyless entry transmitter.

Remote all door unlock: The BCM unlocks all of the vehicle doors when you press UNLOCK on the keyless entry transmitter again within 5 seconds of pressing unlock.

Remote all door lock: The BCM locks all of the vehicle doors when you press LOCK on the keyless entry transmitter.

Refer to Keyless Entry System operation in Keyless Entry for more information about the keyless entry system.

Feature Customization

Automatic Door Lock/Unlock Modes

The four automatic door lock/unlock modes are described in the table below:

Mode

Description

Mode 1

No automatic door lock/unlock (feature disabled).

Mode 2

    • All doors lock when shifting the transaxle out of PARK
    • No automatic door unlock.

Mode 3

    • All doors lock when shifting the transaxle out of PARK.
    • All doors unlock when shifting the transaxle into PARK.

Mode 4

    • All doors lock when shifting the transaxle out of PARK.
    • Driver's door unlock when shifting the transaxle into PARK.

Changing the Automatic Door Lock/Unlock Mode

The two ways to change the automatic door lock/unlock mode are described below:

    • The Tech 2 scan tool method
        Complete the following steps in order to change the automatic door lock/unlock mode using the Tech 2 scan tool method:
       - At the SELECT SYSTEM screen select BODY.
       - Then select the car line and nameplate.
       - At the APPLICATION MENU screen select PERSONALIZATION.
       - At the next APPLICATION MENU screen select SET OPTIONS.
       - At the next APPLICATION MENU screen select the mode you want.
       - The door lock switch method.
    • Refer to Vehicle Personalization/Customization in Entertainment for the second method.

Mode 3 is preset when the vehicle is manufactured. Disconnecting the battery will not change the mode.

Locking Mode for the Last Door Closed

The two locking modes for the last door closed are described below:

    • Mode 1
        The last door closed locking feature is disabled.
    • Mode 2
        The last door closed locking feature is enabled.

Changing the Last Door Locking Mode

The two ways to change the last door locking mode are described below:

    • The Tech 2 scan tool method
        Complete the following steps in order to change the last door locking mode using the Tech 2 scan tool method:
       - At the SELECT SYSTEM screen select BODY.
       - Then select the car line and nameplate.
       - At the APPLICATION MENU screen select PERSONALIZATION.
       - At the next APPLICATION MENU screen select SET OPTIONS.
       - At the next APPLICATION MENU screen select the mode you want.
       - The door lock switch method.
    • Refer to Vehicle Personalization/Customization in Entertainment for the second method.

The last door closed locking mode was enabled when the vehicle was manufactured. Disconnecting the vehicle battery for up to one year will not change the mode.