B2600

DTC B2600

Diagnostic Instructions

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

DTC Descriptor

DTC B2600 00
- Daytime Running Lamp Control Circuit

DTC B2605 00
- Daytime Running Lamp Control 2 Circuit

Diagnostic Fault Information






Circuit/System Description

The daytime running lamps (DRL) are controlled by the body control module (BCM). The BCM grounds the DRL or DRL 2 relay control circuit in order to energize the DRL relay coil. The DRL or DRL 2 relay then sends voltage to the dedicated DRL or low beam headlamps.

Conditions for Running the DTCs

* The headlamp switch is OFF.
* The automatic headlamps are not requested.
* The park brake is unapplied.
* The engine is running.

Conditions for Setting the DTC

The appropriate DRL relay control circuit is shorted to voltage.

Action Taken When the DTC Sets

The BCM turns off the appropriate DRL relay control for the remainder of the ignition cycle.

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.

Circuit/System Verification

Block the drive wheels. Carefully supply sufficient light to simulate daylight conditions to the ambient light sensor. With the engine running, headlamp switch in AUTO, and the park brake released, and the transmission in DRIVE, the DRL should illuminate.

Circuit/System Testing

1. Ignition OFF, disconnect the appropriate DRL relay.
2. Verify that a test lamp does not illuminate between the relay control circuit terminal 85 and ground.

^ If the test lamp illuminates, test the relay control circuit for a short to voltage.

3. If all circuits test normal, test or replace the BCM.

Repair Instructions

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

* Relay Replacement (Attached to Wire Harness) Relay Replacement (Within an Electrical Center)