2010 Cadillac CTS Sedan AWD V6-3.6L Page 503

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

2010 Cadillac Truck Escalade EXT AWD V8-6.2L Page 678

2010 Cadillac Truck Escalade EXT AWD V8-6.2L Page 678

The BCM, driver door switch, and passenger door switch cease attempts to illuminate the courtesy lamps.

Conditions for Clearing the DTC

* The conditions for setting the DTC are no longer present.

* A history DTC clears after 100 malfunction-free ignition cycles.

* The BCM receives the clear code command from the scan tool.

Reference Information

Schematic Reference

Interior Lights Schematics (See: Diagrams/Electrical Diagrams/Lighting and Horns/System Diagram/Interior Lights Schematics)

Connector End View Reference

Component Connector End Views (See: Diagrams/Connector Views)

Description and Operation

Interior Lighting Systems Description and Operation (See: Lighting and Horns/Description and Operation/Interior Lighting Systems Description

and Operation)

Electrical Information Reference

* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Circuit

Testing/Circuit Testing)

* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic

Procedures/Connector Repairs/Connector Repairs)

* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/General

Electrical Diagnostic Procedures/Circuit Testing/Testing for Intermittent Conditions and Poor Connections)

* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Wiring

Repairs/Wiring Repairs)

Scan Tool Reference

Control Module References (See: Testing and Inspection/Programming and Relearning) for scan tool information

Circuit/System Testing

Note: Each courtesy lighting component may need to be disconnected to isolate a short to voltage or short to ground. Use the schematic to identify

the following:

* Courtesy Lighting components the vehicle is equipped with.

* Component locations on the courtesy lighting control circuit

* Each component's control and ground circuit terminals

1. Ignition OFF, disconnect the harness connector at any component with inoperative courtesy lighting.

2. Ignition OFF, scan tool disconnected, interior lamps OFF, doors CLOSED, test for less than 5 ohm between the ground circuit and ground.

瀚慖f greater than the specified value, test the ground circuit for an open/high resistance.

3. Connect a test lamp between the control circuit and ground.

4. Command the Courtesy Lamp control 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 OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace

the BCM.

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 BCM.

5. If all circuits test normal, replace the component with the inoperative courtesy lighting.

Repair Instructions

Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.

* Refer to the appropriate replacement procedure for the component causing the condition.

* Control Module References (See: Testing and Inspection/Programming and Relearning) for BCM replacement, setup, and programming