The body control module (BCM) controls the retained accessory power (RAP) feature.
The BCM controls devices by directly supplying power through the RAP relay, or by
a class 2 command through the instrument panel cluster (IPC). The RAP relay
allows the BCM to directly control the application of power to the following devices:
The IPC monitors the RAP relay control circuit and sends class 2 RAP
commands to the following devices:
• | Vehicle interface unit (VIU), if equipped |
The BCM feature allows for the operation of the above components for 10 minutes,
or until a vehicle door opens, after the ignition switch turns from the RUN to the
OFF position.
When the ignition switch is in either of the following positions, the BCM energizes
the RAP relay by grounding the relay control circuit:
The BCM turns OFF the RAP relay when the ignition switch is in the START position,
thus disabling the RAP feature during the engine crank and bulb test.
When the ignition switch turns from the RUN position to the OFF position with
all of the vehicle doors closed, the BCM leaves the RAP relay energized for 10 minutes
if the vehicle has been driven for more than 15 miles, or until 1 or more
of the following conditions are met:
• | Any vehicle door opens. |
• | The content theft deterrent system goes into the armed mode if equipped
with Content Theft Deterrent System - RPO UA6. |
The BCM resets the RAP timer when the ignition switch turns from the OFF position
to the ACC position.
Diagnostic Aids
The body control module (BCM) monitors the retained accessory power (RAP) relay
control circuit. The BCM sets the DTC 004 when detecting the following conditions:
• | A short to B+ in the relay control circuit |
• | A short to ground in the relay control circuit |
If the power windows operate properly under RAP conditions and the radio or
vehicle interface unit (VIU) do not operate properly, the condition exists in the
class 2 circuit of the radio, VIU, or instrument panel cluster (IPC).
Refer to
Scan Tool Does Not Communicate with Class 2 Device
.