2010 Cadillac Truck SRX AWD V6-3.0L Page 571
Ignition ON, command the Rear Fog Lamp(s) Relay ON and OFF with a scan tool. The rear fog lamp should turn ON and OFF when changing
between the commanded states.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the E5 fog lamp-rear.
2. Test for less than 30 ohm between the ground circuit terminal C and ground.
瀚慖f greater than the specified range, test the ground circuit for an open/high resistance.
3. Connect a test lamp between the control circuit terminal A and ground.
4. Ignition ON, command the Rear Fog Lamp(s) Relay ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing
between the commanded states.
瀚慖f the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the K9 BCM.
瀚慖f 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 BCM.
5. If all circuits test normal, replace the E5 fog lamp-rear.
Repair Instructions
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
* Tail Lamp Replacement (See: Lighting and Horns/Tail Lamp/Service and Repair)
* Control Module References (See: Testing and Inspection/Programming and Relearning) for BCM replacement, setup and programming
B2545
DTC B2545
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System
Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an
overview of the diagnostic approach.
* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure
Instructions) provides an overview of each diagnostic category.
DTC Descriptors
DTC B2545 01
- Backup Lamps Circuit Short to Battery
DTC B2545 02
- Backup Lamps Circuit Short to Ground
DTC B2545 04
- Backup Lamps Circuit Open
Diagnostic Fault Information
Circuit/System Description
When the engine is running and the transmission is placed in reverse gear, the transmission control module 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. Once the driver moves the gear selector out of the reverse position, a message is sent by the transmission control module via serial data
