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 Instructions)provides an overview of each diagnostic category.

DTC Descriptors
DTC B2580 01
- High Beam Control Circuit Short to Battery

DTC B2580 04
- High Beam Control Circuit Open

Diagnostic Fault Information





Circuit/System Description

The headlamp high beam relay is supplied with battery voltage at all times. The turn signal/multifunction switch signal circuit is grounded by pressing the turn signal/multifunction switch. The body control module (BCM) energizes the headlamp high beam relay by applying ground to the headlamp high beam relay control circuit. When the headlamp high beam relay is energized, the relay switch contacts close and battery voltage is applied through the high beam lamp fuses to the high beam lamp supply voltage circuit which illuminates the high beam lamps.

Conditions for Running the DTC

High beam lamps ON.

Conditions for Setting the DTC

B2580 01

The BCM detects a short to voltage in the headlamp high beam relay control.

B2580 04

The BCM detects an open/high resistance in the headlamp high beam relay control.

Action Taken When the DTC Sets

The high beam headlamps will be inoperative.

Conditions for Clearing the DTC

* The DTC will be current for as long as the fault is present.
* When the fault is no longer present, the DTC will be a history DTC.
* A history DTC will clear after 50 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 (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 Relearning)for scan tool information

Circuit/System Verification

Ignition ON, headlamp ON, command the high beam headlamps ON and OFF by applying and releasing the turn signal/multifunction switch. The high beam headlamps should turn ON and OFF when changing between the commanded states.

Circuit/System Testing

1. Ignition OFF, disconnect the X2 harness connector at the X50A underhood fuse block.
2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 58 and ground.

• If the test lamp is ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the K9 BCM.

3. Connect a test lamp between the control circuit terminal 58 and B+.
4. Headlamp ON, command the high beam headlamps ON and OFF by applying and releasing the turn signal/multifunction switch. The test lamp should turn ON and OFF when changing between the commanded states.

• If the test lamp is always OFF, test the control circuit for an open/high resistance. If the circuit tests normal, replace the K9 BCM.
• If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the K9 BCM.

5. If all circuits test normal, replace the X50A underhood fuse block.

Repair Instructions

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

* Fuse Block Replacement (Fuse Block Replacement)
* Control Module References (Programming and Relearning)for BCM, replacement, programming and setup