Retained Accessory Power (RAP) Power Mode
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 BCM.
The BCM:
| • | controls certain body functions. |
| • | 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 (internal to BCM -- if equipped) |
| • | The right and left power rear windows (internal to BCM --
if equipped) |
| • | 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 works in RAP power mode due to the BCM allowing
and controlling it. |
RAP is disabled when:
| • | A low battery voltage is detected by the BCM. |
| • | The transition of ignition switch from OFF to ON or ACC. |
| • | 10 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.
RAP Relay (if equipped)
The long base vehicles (GMT370), with third row seating, will have a
RAP relay (RAP relay is also on the G/H Van). Due to this, the
BCM will power/enable a relay. On the short based vehicles (GMT360), the
RAP output only needs to drive the sunroof. The BCM is able to supply enough
current to operate the sunroof by itself, so a relay is not needed. Although,
on the GMT370/longbase vehicle, there are optional powered rear quarter vent
windows, which are also enabled in RAP power mode. Refer to
Retained Accessory Power (RAP) Schematics
for the applicable schematics
for RAP on both vehicle types. On the GMT370/longbase vehicle, the BCM is
not able to supply enough current to both rear quarter vent windows and the
sunroof at the same time (if equipped with both options). This is the purpose
of the RAP relay. The BCM energizes the RAP relay coil, which allows a fused
power supply to the sunroof and the rear quarter vent windows.
