Operation CHARM: Car repair manuals for everyone.

Retained Accessory Power




Retained Accessory Power Description and Operation

Serial Data Control of Retained Accessory Power (RAP)

The modules receive the power mode message from the body control module (BCM) over the serial data circuits, indicating when the retained accessory power (RAP) power mode is current. The BCM monitors the ignition switch position, battery condition and passenger compartment doors status to determine whether RAP should be initiated. The modules then support the operation of the systems under their control as required by their RAP power mode operation. Components and systems that are active in RAP are also activated anytime the ignition is any position other than OFF.

The BCM sends a serial data power mode message ending the RAP function when one of the following conditions is met:

* The BCM receives an input indicating the opening of any passenger compartment door after the ignition key is out of the ignition.

Important: The only door that will turn off the radio during RAP is the driver door. This is a function of the radio and will still turn off after the time limit.


* The BCM internal timer for the RAP expires after approximately 10 minutes.

* The BCM detects a decrease in battery capacity below a prescribed limit.

BCM Direct Wired Control of Retained Accessory Power (RAP)

The body control module (BCM) supplies voltage to the ignition I/II voltage circuit during all power modes, except Off-Awake and Crank. Voltage is also supplied for approximately 10 minutes after shutting the ignition OFF and removing the key, providing no door is opened.

The devices powered by the accessory relay during the RAP power mode are the sunroof, power window switches, inside rearview mirror, A/C power outlet, and the ignition lock switch.