Serial Data Control of Retained Accessory Power (RAP)

Retained accessory power (RAP) is a vehicle power mode that permits the operation of selected customer convenience items after the ignition switch is turned OFF. These selected items will remain in operation until a passenger compartment door is opened or until the RAP function timer reaches its shut-off limit.

The modules listed below all receive a RAP message from the body control module (BCM) over the serial data circuits. The BCM monitors the ignition switch position, battery condition and passenger compartment door status to determine whether RAP should be initiated. The BCM then sends a message to the listed modules telling them that they are in RAP power mode. The modules then support the operation of the systems under their control as required by their RAP power mode strategy.

RAP will end when 1 of the following conditions are met:

• The BCM receives an input, as a hard wired input from the door switches, indicating the opening of a passenger compartment door.
• The BCM receives a message from its internal timer indicating the end of the RAP period after 10 minutes.
• The BCM detects a decrease in battery capacity below a prescribed limit.
• The transition from OFF to RUN/ON or ACC of the ignition switch.

The BCM then sends a serial data message to the listed devices ending the RAP function.

The devices receiving serial data messages for RAP functions are:

• Auxiliary power drop connector
• Driver information center (DIC)
• Instrument panel cluster (IPC)
• Radio
• Remote CD player, if equipped
• Vehicle interface unit (VIU), if equipped