Conditions for Clearing the DTC

WARNING: This page is about a different car, the 2002 GMC Sierra, 2002 GMC Cab & Chassis Sierra, 2002 Chevrolet Silverado, and 2002 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

A current DTC B1478 will clear if the short to battery in the RAP#1 relay control circuit is no longer detected by the BCM when the RAP#1 relay is commanded to energize.
A history DTC B1478 will clear after the module ignition cycle counter reaches the reset threshold, without a repeat of the malfunction.