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 01
- Headlamp High Beam Control Circuit Short to Battery

DTC B2580 06
- Headlamp High Beam Control Circuit Short to Ground or Open

Circuit/System Description

The high beam relay is controlled by the body control module (BCM). The BCM provides ground to the high beam relay control circuit in order to turn ON the high beam relay. When the high beam relay control circuit opens, becomes shorted to voltage, or becomes shorted to ground without being commanded ON by the BCM, DTC B2580 is set.

Conditions for Running the DTC

The ignition switch is in the ON position.

Conditions for Setting the DTC

B2580 01

Will set if there is a short to voltage in the high beam relay control circuit.

B2580 06

Will set if there is an open or short to ground in the high beam relay control circuit.

Action Taken When the DTC Sets

* If the high beam relay control circuit is shorted to ground, the high beams are always ON.
* If the high beam relay control circuit is open, the high beam lamps are inoperative.

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.

Circuit/System Testing

1. Ignition OFF, disconnect the HI/BEAM relay.
2. Ignition ON, verify that a test lamp illuminates between the B+ circuit of the HI/BEAM relay and ground.

^ If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.

3. Connect a test lamp between the B+ circuit of the HI/BEAM relay and the control circuit of the HI/BEAM relay.
4. Command the backup lamps 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 an open/high resistance. If the circuit tests normal, replace the BCM.

5. If all circuits test normal, replace the HI/BEAM relay.

Repair Instructions

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

* Relay Replacement (Attached to Wire Harness)