Service Information

Volt

DTC B2545

Diagnostic Instructions

•	Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

•	Review Strategy Based Diagnosis for an overview of the diagnostic approach.

•	Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC B2545 01: Reverse Lamps Circuit Short to Battery

DTC B2545 02: Reverse Lamps Circuit Short to Ground

DTC B2545 04: Reverse Lamps Circuit Open

Diagnostic Fault Information

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
F7DR (interior lamps) Fuse B+	B2545 01, B2545 04, B2615 02	B2545 01, B2545 04, B2615 02	--	--
Reverse Lamp Control	B2545 02	B2545 01, B2545 04	1	--
Reverse Lamp Ground	--	1	--	--
1. 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.

Conditions for Running the DTC

•	Vehicle ON.

•	Transmission in REVERSE gear.

Conditions for Setting the DTC

DTC B2545 01 and B2545 04

•	The BCM detects an open/high resistance in the reverse lamp control circuit.

•	The BCM detects a short to ground or an open/high resistance in the F7DR fuse B+ circuit.

DTC B2545 02

The BCM detects a short to ground in the reverse lamp control circuit.

Action Taken When the DTC Sets

The reverse lamp will not operate.

Conditions for Clearing the DTC

•	The condition responsible for setting the DTC no longer exists.

•	A history DTC will clear once 100 consecutive malfunction free vehicle ON/OFF switch cycles have occurred.

Reference Information

Schematic Reference

•	Exterior Lamps Schematics

•	Body Control System Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Exterior Lighting Systems Description and Operation

Electrical Information Reference

•	Circuit Testing

•	Connector Repairs

•	Testing for Intermittent Conditions and Poor Connections

•	Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing

Vehicle OFF, disconnect the X5 harness connector at the K9 Body Control Module.
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.

Vehicle OFF, connect the X5 harness connector at the K9 Body Control Module.
Disconnect the harness connector at the E5 Reverse Lamp.
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.

Connect a test lamp between the control circuit terminal A and ground.
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.

If all circuits test normal, replace the E5 Reverse Lamp.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

•	Reverse Lamp Bulb Replacement

•	Control Module References for BCM replacement, programming and setup