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 00
- Headlamp High Beam Control Circuit

Diagnostic Fault Information






Circuit/System Description

Voltage is applied at all times to the high beam headlamp relay from battery voltage. When the multifunction switch is placed in either the FTP or HIGH position, ground is applied to the body control module (BCM). The BCM then applies a ground to the high beam headlamp relay control circuit. This engages the relay and applies voltage through the HIGH beam fuses to both the left and right high beam headlamps.

Conditions for Running the DTC

The ignition is ON. The high beam headlamps must be commanded ON by the multifunction switch.

Conditions for Setting the DTC

The BCM detects a short to voltage on the low beam headlamps relay control circuit while trying to apply a ground to the circuit.

Action Taken When the DTC Sets

The high beam headlamps are inoperative.

Conditions for Clearing the DTC

The BCM clears this code from current when the fault is removed from the system.

Circuit/System Verification

Ignition ON, turn the headlamps ON. The headlamps should illuminate.

Circuit/System Testing

1. Clear the DTC, ignition OFF, headlamp switch OFF, disconnect the high beam headlamp relay.
2. Verify a test lamp illuminates between the negative battery terminal and the high beam headlamp relay control circuit.

• If the test lamp does not illuminate, replace the underhood fuseblock.

3. Test for a short to voltage in the high beam headlamp relay control circuit.

• If all circuits/connections test normal, replace the BCM.

Repair Instructions

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

* Underhood Electrical Center or Junction Block Replacement