DTC B2477, Reverse Relay Shorted To Ground: Notes
WARNING: This page is about a different car, the 1997 Cadillac Seville, 1997 Cadillac Eldorado, and 1997 Cadillac DeVille. However, it is still accessible from the selected car via links, so may be relevant.
When PZM receives input that transaxle is in reverse, PZM energizes reverse relay which will turn on back-up lights. When back-up lights have been commanded on, PZM constantly measures voltage at 32-pin connector C2 terminal D3 (Dark Green wire). DTC B2477 will set when voltage is approximately equal to ground. DTC B2477 will clear when voltage is greater than ground for at least one monitoring cycle.