GM Service Manual Online
For 1990-2009 cars only

Serial Data Control of Retained Accessory Power, RAP

The Radio receives a RAP message from the Body Control Module, BCM over the serial data circuits. The BCM module monitors the ignition switch position, battery condition and passenger compartment door status to determine whether RAP should be initiated. The BCM module then sends a message to the Radio telling it that it is in RAP power mode.

RAP will end when one of the following conditions are met:

    • The BCM module receives an input from the drivers door jam switch.
    • The BCM module receives a message from its internal timer indicating the end of the RAP period after 10  minutes.
    • The BCM module detects a decrease in battery capacity below a prescribed limit.
    • The transition from OFF to RUN/ON or ACC of the ignition switch.

The BCM module then sends a serial data message to the Radio ending the RAP function.