GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2003 🢒 Avalanche - 4WD 🢒 Body and Accessories 🢒 Instrument Panel, Gages, and Console 🢒 Retained Accessory Power Description and Operation

Retained Accessory Power (RAP) Power Mode

Retained accessory power (RAP) is a power mode that permits the operation of selected customer convenience items for 10 minutes after the ignition switch is turned OFF. RAP power mode is enabled by the body control module (BCM).

    • The BCM controls certain body functions.
    • The BCM sends out a class 2 message via the serial data line, which enables/disables other modules at the beginning/end of RAP power mode.

Some BCM features, such as the interior courtesy lamps will function after the 10 minute RAP time limit has elapsed. This is normal, and does not mean RAP power mode is malfunctioning. The BCM enables the following functions in RAP Power Mode:

    • The sunroof, if equipped
    • The right and left power rear windows
    • Any class 2 module that functions in RAP power mode, that is not hard-wired, is controlled by the BCM via class 2 power mode messages. EXAMPLE: The Radio will power up if it is turned ON and the BCM transmits a RAP, Run or Accessory message over the class 2 serial data bus.

RAP is disabled when:

    • A door is opened.
    • A low battery voltage is detected by the BCM.
    • The transition of ignition switch from OFF to ON or ACC.
    • Ten minutes have elapsed after the ignition was turned OFF.
    • There may be some functions of the vehicle that are hard-wired straight to the battery, these are the exceptions.

The BCM monitors the ignition switch position, battery voltage and passenger compartment door status to determine whether RAP power mode should be enabled. If the ignition switch transitions from ON to OFF, the battery voltage is within the acceptable range and the passenger compartment doors are closed, the BCM enables RAP power mode. After the 10 minutes has elapsed, the BCM sends a class 2 message to the serial data network. This message commands the other modules to stop functioning, that are power moded by the BCM.

Sunroof Relay (If Equipped)

The BCM has a discrete output used for the control of the sunroof relay. In the RAP power mode the BCM will supply a B+ to the control circuit to enable the relay. The BCM also enables the relay in the Accessory and Run power modes. Refer to Retained Accessory Power (RAP) Schematics to become familiar with the system and for the circuit identification.