B2580

DTC B2580

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 B2580
- Headlamp High Beam Control Circuit

Diagnostic Fault Information






Circuit/System Description

When the body control module (BCM) receives a ground signal from the multifunction high beam or flash to pass (FTP) switch commanding to illuminate the high beam headlamps, the BCM will energize the high beam relay by grounding the high beam relay control circuit.

Conditions for Running the DTC

The battery voltage must be between 9-16 volts.

Conditions for Setting the DTC

* When the BCM receives a high beam headlamp request the high beam headlamp relay control circuit is shorted to voltage.
* When the BCM is not receiving a high beam headlamp request the high beam headlamp relay control circuit is open or shorted to ground.

Action Taken When the DTC Sets

The high beam headlamps are inoperative or always on.

Conditions for Clearing the DTC

* This DTC will clear on current status after the condition for setting the fault is corrected.
* A history DTC will clear after 100 consecutive ignition cycles without a fault present.

Circuit/System Testing

1. Ignition OFF, disconnect the high beam headlamp relay.
2. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 85 and ground.

^ If the test lamp does not illuminate and the fuse is not open, replace the underhood fuse block.

3. Connect a test lamp between the relay control circuit terminal 86 and B+.
4. Operate the high beam headlamps ON and OFF. 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 an open/high resistance. If the circuit tests normal, replace the BCM.

5. If all circuits test normal replace the high beam headlamp relay.

Repair Instructions

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