DTC B1477: Rap Relay Circuit (Short To Ground Or Open): Description

WARNING: This page is about a different car, the 1999 Buick Regal and 1999 Buick Century. However, it is still accessible from the selected car via links, so may be relevant.

Body Control Module (BCM) completes Retained Accessory Power (RAP) relay circuit when ignition switch is turned from RUN or ACC position to LOCK/OFF position by grounding circuit No. 707 (Black wire). RAP relay is de-energized after a 10-minute period or when any vehicle door is opened. BCM monitors voltage level on control circuit No. 707. When RAP relay is energized, BCM can control application of power to radio, power windows and power sun roof. RAP feature is not available on the Century Custom model.

DTC B1477 will set when BCM detects a short to ground or open in circuit No. 707 (Black wire) for more than 0.3 second when it is attempting to de-energize RAP relay. No driver warning message will be displayed.

If conditions for malfunction no longer exist, history DTC will clear after 100 consecutive ignition cycles. DTC B1477 will also clear when conditions no longer exist or scan tool is used to clear codes.

NOTE: If DTC B1477 is a history code, problem may be intermittent. Wiggle wires while performing the following test.

NOTE: When ignition switch is turned to RUN position with BCM disconnected, PCM-related DTC P1626 will be set. After BCM repair is completed, see appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE.