Serial Data Control of Retained Accessory Power (RAP)
The modules listed below all receive a retained accessory power (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 a hardwired input 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 BCM then sends a serial data message to the listed modules ending the RAP
function.
The modules receiving serial data messages for RAP functions are:
| • | Vehicle interface unit (VIU) (if equipped) |
| • | Instrument panel cluster (IPC) |
| • | HVAC control module (w/CJ2) |
Relay Control of Retained Accessory Power (RAP)
When the body control module (BCM) is in the retained accessory power (RAP)
function as described above, it closes the RAP relay. This provides power during the
RAP period for the following:
The BCM opens the RAP relay to end the RAP function when it ends the RAP function
as outlined in the previous text.
