Accessory Delay Module: Description and Operation

The Body Control Module (BCM) controls the Retained Accessory Power (RAP) feature. The BCM feature allows for the operation of some vehicle components for 10 minutes, or until a door opens, after the ignition switch turns from the RUN to the OFF position.

The BCM interfaces with the vehicle's power distribution through the RAP relay. The RAP relay allows the BCM to control the application of power to the following devices:
^ The radio
^ The power windows
^ The power sunroof, if equipped

When the ignition switch is in either of the following positions, the BCM energizes the RAP relay by grounding the relay control circuit:
^ ACC
^ RUN

The BCM turns OFF the RAP relay when the ignition switch is in the START position, thus disabling the RAP feature during the engine crank and bulb test.

When the ignition switch turns from the RUN position to the OFF position with all of the vehicle doors closed, the BCM leaves the RAP relay energized for 10 minutes, or until 1 or more of the following conditions are met:
^ Any vehicle door opens.
^ The content theft deterrent system goes into the armed mode, if equipped with Content Theft Deterrent System- RPO UA6.

The BCM resets the RAP timer when the ignition switch turns from the OFF position to the ACC position.

NOTE: The BCM has an inadvertent load, battery rundown protection, which is mileage-sensitive. Vehicles with less than 15 total driven miles have a 3 minute RAP time-out, instead of 10 minutes of RAP.

DIAGNOSTIC AIDS
The BCM monitors the RAP relay control circuit. The BCM sets the Diagnostic Trouble Code (DTC) 004 when detecting the following conditions:
^ A short to B+ in the relay control circuit
^ A short to ground in the relay control circuit.

"For a description of the RPO Code(s) shown in this article or any of the images therein, refer to the RPO Code List found at Vehicle/Application ID". RPO Codes