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 Descriptor
DTC B2580 00
- 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 V.

Conditions for Setting the DTC

The high beam headlamp relay control circuit is shorted to voltage.

Action Taken When the DTC Sets

The high beam headlamps will not operate or will remain 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.

Reference Information
Schematic Reference

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

Programming and Relearning (Programming and Relearning) for scan tool information

Circuit/System Verification

Ignition ON, command the High Beams ON and OFF with a scan tool. The high beams should turn ON and OFF as commanded.

Circuit/System Testing

1. Ignition OFF, disconnect the headlamp high beam relay.
2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 87 and ground.

• If the test lamp illuminates, test the control circuit for a short to voltage.

3. Verify that a test lamp illuminates between the B+ circuit terminal 85 and ground.

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

4. Verify that a test lamp illuminates between the B+ circuit terminal 30 and ground.

• If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.

5. Disconnect the harness connector at the appropriate headlamp - high beam.
6. Test for less than 5 ohm between the headlamp ground circuit terminal listed below and ground:

* RPO TVD/W49
* RPO W49- Terminal 1
* RPO WDA - Terminal 3
* RPO Z88 - Terminal I
* Without RPO TVD/W49 - Terminal A

• If greater than the specified range, test the ground circuit for an open/high resistance.

7. Connect the harness connector at the headlamp - high beam.
8. Connect a 10 A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87. Verify the headlamp - high beam is activated.

• If the headlamp - high beam does not activate and the jumper wire fuse is good, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the headlamp - high beam.
• If the headlamp - high beam does not activate and the jumper wire fuse is open, test the control circuit for a short to ground. If the circuit tests normal, test or replace the headlamp - high beam.

9. Connect a test lamp between the B+ circuit terminal 85 and the control circuit terminal 86.
10. 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 an open/high resistance. If the circuit tests normal, replace the BCM.

11. If all circuits test normal, test or replace the headlamps high beam relay.

Repair Instructions

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

* Relay Replacement (Attached to Wire Harness) (Service and Repair)
* Headlamp Replacement (Traverse with TVP) (Service and Repair)Headlamp Replacement (Acadia) (Service and Repair)Headlamp Replacement (Enclave) (Service and Repair)
* Control Module References (Programming and Relearning) for BCM replacement, setup, and programming