Volt

Reverse Lamps Malfunction

With the vehicle ON and the transmission in the REVERSE position, the transmission control module (TCM) sends a serial data message to the body control module (BCM). The message indicates that the gear selector is in the REVERSE position. The BCM applies battery voltage to the reverese lamp control circuit illuminating the reverse lamps. Once the driver moves the gear selector out of the REVERSE position, a message is sent by the TCM via serial data requesting the BCM to remove battery voltage from the reverse lamps control circuit. The engine must be ON for the reverse lamps to operate.

Schematic Reference

Connector End View Reference

Component Connector End Views

Description and Operation

Exterior Lighting Systems Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

1. Vehicle OFF, disconnect the X5 harness connector at the K9 Body Control Module.
2. Vehicle in Service Mode, verify that a test lamp illuminates between the B+ circuit terminal 4 and ground.

⇒	If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.

3. Vehicle OFF, connect the X5 harness connector at the K9 Body Control Module.
4. Disconnect the harness connector at the E5 Reverse Lamp.
5. Vehicle OFF, exterior lamps OFF, test for less than 5 Ω between the ground circuit terminal B and ground.

⇒	If greater than the specified range, test the ground circuit for an open/high resistance.

6. Connect a test lamp between the control circuit terminal A and ground.
7. Vehicle in Service Mode, command the Reverse Lamps ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

⇒	If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the K9 Body Control Module.

⇒	If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K9 Body Control Module.

8. If all circuits test normal, replace the E5 Reversing Light.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.