B2575
DTC B2575
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.
DTC Descriptor
DTC B2575 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.
Reference Information
Schematic Reference
Headlights/Daytime Running Lights (DRL) Schematics (Headlights/Daytime Running Lights (DRL) Schematics)
Connector End View Reference
Component Connector End Views (Connector 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
Control Module References (Programming and Relearning) for scan tool information
Circuit/System Verification
Ignition ON, command the Low Beam ON with a scan tool. The Low Beam Relay Command parameter 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 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, 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))
* Control Module References (Programming and Relearning) for BCM replacement, setup, and programming