B2575

DTC B2575

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 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 LO BEAM relay coil. The 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.
* The BCM receives the clear code command from the scan tool.



Reference Information
Schematic Reference

Headlights/Daytime Running Lights (DRL) Schematics (Headlights/Daytime Running Lights (DRL) Schematics)
Connector End View Reference

Component Connector End Views (Component Connector End Views)
Description and Operation

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

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Programming and Relearning (Programming and Relearning)for Scan Tool Information


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 (Verification Tests) after completing the diagnostic procedure.

* Relay Replacement (Attached to Wire Harness) (Relay Replacement (Attached to Wire Harness))Relay Replacement (Within an Electrical Center) (Relay Replacement (Within an Electrical Center))
* Programming and Relearning (Programming and Relearning)for BCM replacement, setup, and programming