B2580

DTC B2580

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 Instructionsprovides an overview of each diagnostic category.

DTC Descriptor
DTC B2580 00
- Headlamp High Beam Control Circuit

Diagnostic Fault Information






Circuit/System Description

When the turn signal/multifunction switch is placed in the headlamps high or flash to pass (FTP) position, ground is applied to the body control module (BCM) through the headlamp high beam signal circuit or the flash to pass signal circuit. The BCM applies ground to the headlamp HIGH BEAM relay control circuit which energizes the HIGH BEAM relay. With the HIGH BEAM relay energized, the switch contacts close allowing B+ to flow through the HI BEAM fuses to the high beam headlamps.

Conditions for Running the DTC

* Battery voltage must be between 9-16 V.
* Headlamps ON.

Conditions for Setting the DTC

The BCM detects a short to voltage in the headlamp HIGH BEAM relay control circuit.

Actions Taken When the DTC Sets

The high beam headlamps and flash to pass (FTP) will not operate.

Conditions for Clearing the DTC

* The condition responsible for setting the DTC no longer exists.
* A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Reference Information
Schematic Reference

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

Component Connector End Views Connector End Views By Name
Description and Operation

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

* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs

Scan Tool Reference

Control Module References Programming and Relearningfor scan tool information

Circuit/System Testing

1. Ignition OFF, disconnect the X4 harness connector at the underhood fuse block.
2. Connect a test lamp between the control circuit terminal C3 and B+.
3. Command the High Beams ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

• If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM.
• If the test lamp is always OFF, test the control circuit for a short to voltage or open/high resistance. If the circuit tests normal, replace the BCM.

4. If all circuits test normal, test or replace the underhood fuse block.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.

* Underhood Electrical Center or Junction Block Replacement Underhood Electrical Center or Junction Block Replacement
* Control Module References Programming and Relearningfor BCM replacement, setup, and programming