B2575

DTC B2575

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 2575 00
- Headlamp Control Circuit

Diagnostic Fault Information






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 HID/LO BEAM relay coil. The HID/LO BEAM relay then sends voltage to the low beam headlamps.

Conditions for Running the DTCs

* 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.

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, disconnect the HID/LO BEAM relay.
2. Ignition ON, verify that a test lamp does not illuminate between the relay coil control circuit terminal 86 and ground.

^ If the test lamp illuminates, test the 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)