Buick Regal: 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 02
Backup Lamps Circuit Short to Ground
DTC B2545 04
Backup Lamps Circuit Open
Diagnostic Fault Information
1. Backup Lamps Malfunction
Circuit/System Description
With the engine running 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
backup lamps control
circuit illuminating the backup 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 backup lamps control circuit. The engine must be running for the backup
lamps to operate.
Conditions for Running the DTC
- Battery voltage must be between 9-16 V.
- Engine RUNNING.
- Transmission placed in REVERSE gear.
Conditions for Setting the DTC
DTC B2545 02
The BCM detects a short to ground in the backup lamps control circuit.
DTC B2545 04
The BCM detects an open/high resistance in the backup lamps control circuit.
Actions Taken When the DTC Sets
The backup lamps 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 ignition
cycles have occurred.
Reference Information
Schematic Reference
- Exterior Lights Wiring Schematics
- Body Control System Wiring Schematics
Connector End View Reference
COMPONENT CONNECTOR END VIEWS - INDEX
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
1. Ignition OFF, exterior lamps OFF, disconnect the harness connector at the
appropriate E5 Backup
Lamp. It may take up to 2 min for all vehicle systems to power down.
2. Test for less than 5 Ω between the ground circuit at the socket terminal and
ground.
- Ignition OFF.
- Test for less than 2 Ω in the ground circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, repair the open/high resistance in the ground
connection.
- Go to next step: If less than 5 Ω
3. Connect a test lamp between the control circuit at the socket terminal and
ground, ignition ON.
4. Verify the test lamp turns ON and OFF when commanding the Backup Lamps ON and
OFF with a
scan tool.
- If the test lamp is always OFF
- Ignition OFF, disconnect the X7 harness connector at the K9 Body Control
Module.
- Test for infinite resistance between the control circuit and ground.
- If less than infinite resistance, repair the short to ground on the
circuit.
- Go to next step: If infinite resistance
- Test for less than 2 Ω in the control circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K9 Body Control Module.
- If the test lamp is always ON
- Ignition OFF, disconnect the X7 harness connector at the K9 Body Control
Module, ignition
ON.
- Test for less than 1 V between the control circuit terminal and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, replace the K9 Body Control Module.
- Go to next step: If the test lamp turns ON and OFF
5. Test or replace the E5 Backup Lamp.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
- Tail Lamp Replacement (5-Door Hatchback 68) Tail Lamp Replacement
(5-Door Wagon 35)
- Control Module References for BCM replacement, programming, and setup.
READ NEXT:
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.
Diag
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.
Diag
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.
Diag
SEE MORE:
The exterior lamp control is on the
instrument panel to the left of the
steering column.
There are four positions.
: Turns the exterior lamps off and
deactivates the AUTO mode. Turn
to again to reactivate the
AUTO mode.
In Canada, the headlamps will
automatically reactivate when the
vehicle is
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 Descriptor
DT