DTC B1477: Retained Accessory Power Circuit Low: Description

WARNING: This page is about a different car, the 2002 Chevrolet Monte Carlo, 2002 Chevrolet Impala, 2001 Chevrolet Monte Carlo, and 2001 Chevrolet Impala. However, it is still accessible from the selected car via links, so may be relevant.

Body Control Module (BCM) interfaces with vehicle's power distribution system through Retained Accessory Power (RAP) relay. RAP relay allows BCM to control application of power to feed circuits to sunroof and power windows. When ignition switch is in either ACC or RUN position, BCM energizes RAP relay by applying battery voltage to RAP relay control circuit.

BCM turns off RAP relay when ignition switch is in START position. RAP feature therefore disables during engine cranking. When ignition switch turns from RUN or ACC to LOCK or OFF, with all of vehicle doors closed, BCM leaves RAP relay energized for 10 minutes, or until any vehicle door opens and BCM detects a ground signal in one of door ajar circuits.

DTC B1477 is set when BCM detects no voltage at RAP relay control circuit when BCM is trying to energize RAP relay. Problem must be present for more than 30 seconds.

When DTC B1477 is set, BCM stores DTC B1477 in memory. RAP relay powered functions will not operate. Circuits powered by RAP relay will never be powered if relay control circuit is open.

Current DTC B1477 clears and becomes a history DTC when malfunction is no longer present. History DTC clears when module ignition cycle counter reaches reset threshold, without a repeat of malfunction.