DTC B1477: Retained Accessory Power Circuit Low: Description

BCM control Retained Accessory Power (RAP) feature. RAP feature allows radio, power windows and power sun roof (if equipped) operate for 10 minutes (or until door opens) after ignition switch turns from RUN or ACC to LOCK position. BCM interfaces with vehicles power distribution system through RAP relay. RAP relay allows BCM to control application of power to circuit between RAP relay and RTD ACCSRY PWR BRKR which powers feed circuits to sun roof and power windows. When ignition switch is in ACC or RUN positions, BCM energizes RAP relay.

BCM turns off RAP relay when ignition switch is in START position. RAP feature disables during engine crank and bulb test. When ignition switch turns from RUN to LOCK or OFF and all doors are closed, BCM leaves RAP relay energized for 10 minutes or until any door opens, detected by BCM through ground signal in one of the door ajar circuits. If BCM detects a short to ground for more than 0.3 seconds in RAP relay control circuit when trying to energize RAP relay, DTC B1477 will set to memory. DTC B1477 will clear when fault is no longer detected by BCM. A history DTC B1477 will clear after 100 consecutive ignition cycles if condition for fault no longer exists. A scan tool can clear DTC B1477.