B2600

DTC B2600

DTC DESCRIPTOR

DTC B2600 00
Daytime Running Lamp Control Circuit

DIAGNOSTIC FAULT INFORMATION




Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview

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

CONDITIONS FOR RUNNING THE DTCS
- The headlamp switch is OFF.
- The park brake is unapplied.
- The engine is running.

CONDITIONS FOR SETTING THE DTC
The DRL relay control circuit is shorted to voltage.

ACTION TAKEN WHEN THE DTC SETS
The BCM turns off the 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.
- The BCM receives the clear code command from the scan tool.

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, the DRL should illuminate.

CIRCUIT/SYSTEM TESTING
1. Ignition OFF, disconnect the BCM connector C4.
2. Ignition ON, test for voltage at the BCM harness connector terminal 23.
- If voltage is present, test the control circuit for a short to voltage. If all circuits/connections test normal, replace the underhood fuse block.
- If voltage is not present, replace the BCM.

REPAIR INSTRUCTIONS
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
- Underhood Electrical Center or Junction Block Replacement
- Control Module References for BCM replacement, setup, and programming. Verification Tests Programming and Relearning