B263A

DTC B263A

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.

DTC Descriptor
DTC B263A 02
- Exterior Illumination Lamp Circuit Short to Ground

Diagnostic Fault Information





Circuit/System Description

The outside mirror courtesy lamps illuminate when the doors are unlocked or locked. When the body control module (BCM) receives a request from the key fob to turn ON the park lamps the BCM a sends out a PWM signal, which illuminates the outside courtesy lamps.

Conditions for Running the DTC

The doors are locked or unlocked.

Conditions for Setting the DTC

The control module detects a short to ground on the outside mirror courtesy lamp control circuit.

Action Taken When the DTC Sets

The outside mirror courtesy lamps are inoperative.

Conditions for Clearing the DTC

The condition for setting the DTC is no longer present.

Reference Information
Schematic Reference

Exterior Lights Schematics (Exterior Lights Schematics)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Exterior Lighting Systems Description and Operation (Exterior Lighting Systems Description and Operation)
Electrical Information Reference

* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing For Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information

Circuit/System Verification

Command the Outside Rear View Mirror Courtesy Lamp ON and OFF with a scan tool. The outside rear view mirror courtesy lamps should turn ON and OFF when changing between the selected states.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the appropriate A9 outside rearview mirror.
2. Test for less than 5 ohm between the ground circuit harness connector terminal 4 and ground.

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

3. Connect a test lamp between the control circuit harness connector terminal 17 and ground.
4. Command the Outside Rear View Mirror Courtesy Lamp 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 BCM.
• 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 BCM.

5. If all circuits test normal, test or replace the A9 outside rearview mirror.

Repair Instructions

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

* Outside Rearview Mirror Replacement (Outside Rearview Mirror Replacement)
* Control Module References (Programming and Relearning) for BCM replacement, setup and programming