2010 Cadillac CTS Sedan AWD V6-3.6L Page 503
the BCM.
9. If all circuits test normal, replace the tail lamp.
Repair Instructions
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
* Tail Lamp Replacement (Sedan, V-Series) (See: Lighting and Horns/Tail Lamp/Service and Repair)Tail Lamp Replacement (Wagon) (
See: Lighting and Horns/Tail Lamp/Service and Repair)
* Inside Rearview Mirror Replacement (See: Body and Frame/Mirrors/Service and Repair/Inside Rearview Mirror Replacement)
* Control Module References (See: Testing and Inspection/Programming and Relearning) for BCM replacement, setup, and programming
B2555
DTC B2555
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 B2555 01
- Passenger Compartment Lamp Control Circuit Short to Battery
DTC B2555 02
- Passenger Compartment Lamp Control Circuit Short to Ground
Diagnostic Fault Information
Circuit/System Description
The body control module (BCM) applies battery voltage to the courtesy lamps through the courtesy lamp supply voltage circuit. When any door is
opened, the jam switch contacts close and the BCM receives a door-open input. If the BCM receives a door lock or unlock input or a rear hatch
open input, the BCM will activate the courtesy lamp supply voltage circuit, providing battery voltage to all of the instrument panel (I/P) courtesy
lamps, dome lamps, rearview mirror lamps, and rear compartment lamps. The BCM also provides a serial data message to the driver door module
