DTC B1477: Retained Accessory Power (Rap) Circuit Low: Description
WARNING: This page is about a different car, the 2001 GMC Safari and 2001 Chevrolet Astro. However, it is still accessible from the selected car via links, so may be relevant.
Retained Accessory Power (RAP) function allows radio, power windows and driver information center (if equipped) to operate with doors closed and ignition off for up to 20 minutes. BCM monitors ignition switch position, door jamb switches and voltage on RAP relay control circuit. BCM will command RAP relay ON by grounding RAP relay control circuit when all doors are CLOSED and ignition switch is switched to OFF position. If BCM does not detect battery voltage on RAP relay control circuit with RAP relay commanded ON. System voltage must be between 9.0-16.0 volts. If these conditions are met for 0.5 seconds a DTC will be set.