Operation CHARM: Car repair manuals for everyone.

General Information

The Body Control Module (BCM) controls the Retained Accessory Power (RAP) feature. The BCM controls devices by directly supplying power through the RAP relay, or by a Class 2 command through the Instrument Cluster (IPC). The RAP relay allows the BCM to directly control the application of power to the following devices:
^ Power windows
^ Rear quarter windows.

The IPC monitors the RAP relay control circuit and sends Class 2 RAP commands to the following devices:
^ Radio
^ Vehicle Interface Unit (VIU) (if equipped).

The BCM feature allows for the operation of the above components for 10 minutes (or until a vehicle door opens) after the ignition switch turns from the RUN to the OFF position.

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 (see note), 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.

"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