Retained Accessory Power

Retained Accessory Power Description and Operation

Retained Accessory Power (RAP)

The retained accessory power (RAP) system allows specific vehicle functions to operate for a specific amount of time after the ignition switch is turned OFF. The BCM monitors the ignition switch position, battery condition, and each door open/closed status to determine whether RAP should be initiated or terminated. RAP is controlled with 2 different methods; serial data and relay control. The relay is internal to the BCM and feeds multiple external components. Some modules receive a RAP message over the serial data circuits. Serial data controlled RAP is deactivated as required by their modules RAP power mode operation. Other subsystems are activated directly by the BCM through the internal RAP relay. Components and systems that are active in RAP are also activated anytime the ignition is any position other than OFF regardless of the door switch signals.

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

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

Note: 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 RAP expires after approximately 10 minutes.
* The BCM detects a decrease in battery voltage below a calibrated limit.

Relay Control of Retained Accessory Power (RAP)

The body control module (BCM) keeps the internal RAP relay energized during all power modes, except Off-Awake and Crank. The relay is also energized for approximately 10 minutes after shutting the ignition OFF and removing the key, providing no door is opened. The BCM will de-energize the internal RAP relay at the same time the serial data message is sent to end RAP. When the internal RAP relay is energized voltage is applied on the accessory voltage circuit at BCM harness connector X5 terminal 11.

The devices powered by the internal RAP relay during the RAP power mode are the sunroof (CF5), the RAP/Spare PCB relay, and if equipped with RPO 9L4, the radio module fuse block relay A.

Serial Data Control of Retained Accessory Power (RAP)

RAP systems controlled by serial data are as follows:

Power Windows

Window RAP activation/termination timing is the same as relay operation. The front window switches are separate modules that operate the windows on their respective side of the vehicle.

Vehicle Communication Interface Module (VCIM) (Onstar(R))

VCIM RAP activation/termination is the same as radio operation with 1 exception; if there is an active call when the ignition key is turned off the VCIM will remain in RAP mode and keep the radio in RAP mode until the call is terminated.

Radio

Radio RAP activation/termination is the same as relay operation with 1 exception; the only door switch that will turn off the radio during RAP is the driver door open switch.