B2575

DTC B2575

DTC DESCRIPTOR

DTC 2575 00
Headlamp 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 low beam headlamps are controlled by the body control module (BCM). The BCM grounds the headlamp low beam relay control circuit in order to energize the LO BEAM relay coil. The LO BEAM relay then sends voltage to the low beam headlamps.

CONDITIONS FOR RUNNING THE DTC
- The headlamps are commanded ON.
- The headlamp dimmer switch must be in the low beam position.

CONDITION FOR SETTING THE DTC
The headlamp low beam relay control circuit is shorted to voltage.

ACTION TAKEN WHEN THE DTC SETS
The BCM turns off the headlamp low beam 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
Ignition ON, activate the Low Beam output control on the scan tool. The Low Beam Relay Command parameter in the data list should display On and the low beam headlamps should illuminate.

CIRCUIT/SYSTEM TESTING
1. Ignition OFF, remove the low beam relay in the underhood fuse block.
2. Ignition ON, test for voltage at the relay control circuit terminal of the underhood fuse block.
- If voltage is present, test the control circuit for a short to voltage. If all circuits/connections test normal, replace the low beam relay.
- If voltage is not present, replace the BCM.

REPAIR INSTRUCTIONS
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
- Relay Replacement (Attached to Wire Harness) Relay Replacement (Within an Electrical Center)
- Control Module References for BCM replacement, setup, and programming Verification Tests Programming and Relearning