When the body control module (PZM) receives a class 2 serial data message that the transaxle is in reverse, the PZM energizes the reverse lamp relay and the backup lamps are turned on. When the PZM has not commanded the backup lamps on, the voltage at connector C2 terminal D14 is measured every 1000 ms.

The PZM determines the voltage at connector C2 terminal D14 is approximately equal to ground.

The PZM determines the voltage at connector C2 terminal D14 is greater than ground for at least 1 monitoring cycle.

Inspect CKT 646 (DK GRN) for a short to ground.