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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
- Headlamp High Beam Control Circuit Short to Battery

DTC B2580 02
- Headlamp High Beam Control Circuit Short to Ground

DTC B2580 04
- Headlamp High Beam Control Circuit Open

Diagnostic Fault Information





Circuit/System Description

When the turn signal/multifunction switch is placed in the headlamps high or flash to pass position, ground is applied to the body control module (BCM) through the headlamp high beam signal circuit or the flash to pass switch signal circuit. The BCM applies ground to the headlamp high beam relay control circuit which energizes the high beam relay. With the high beam relay energized, the switch contacts close allowing battery voltage to flow through the left and right HIGH BEAM fuses to the high beam headlamps.

Conditions for Running the DTC

* Battery voltage must be between 9-16 V.
* High beam headlamps ON.

Conditions for Setting the DTC

B2580 01

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

B2580 02

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

B2580 04

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

Actions Taken When the DTC Sets

The high beam headlamps and flash to pass will not operate.

Conditions for Clearing the DTC

* The condition responsible for setting the DTC no longer exists.
* A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

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, headlamps ON, turn the high beam headlamps ON and OFF using the Turn Signal/Multi-Function Switch. The high beam headlamps should turn ON and OFF when changing between the selected states.

Circuit/System Testing

1. Ignition OFF, disconnect the KR48 Headlamp High Beam Relay.
2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 30 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 86 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 87 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 E4 Headlamp - High Beam.
6. Test for less than 5 ohm between the ground circuit terminal B and ground.

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

7. Connect the harness connector at the E4 Headlamp - High Beam.
8. Connect a 10 A fused jumper wire between the B+ circuit terminal 87 and the control circuit terminal 30. Verify the E4 Headlamp - High Beam is activated.

If the E4 Headlamp - High Beam does not activate and the circuit fuse is good, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the E4 Headlamp - High Beam.
If the E4 Headlamp - High Beam does not activate and the circuit fuse is open, test the control circuit for a short to ground. If the circuit tests normal, test or replace the headlamp.

9. Connect a test lamp between the B+ circuit terminal 86 and the control circuit terminal 85.
10. Turn the high beam headlamps ON and OFF using the S78 Turn Signal/Multi-Function Switch. The test lamp should turn ON and OFF when changing between the selected states.

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.
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 K9 BCM.

11. If all circuits test normal, test or replace the KR48 Headlamp High Beam Relay.

Repair Instructions

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

* Relay Replacement (Attached to Wire Harness) (Relay Replacement (Attached to Wire Harness))Relay Replacement (Within an Electrical Center) (Relay Replacement (Within an Electrical Center))
* Headlamp Replacement (Equinox) (Service and Repair)Headlamp Replacement (Terrain) (Service and Repair)
* Control Module References (Programming and Relearning) for BCM replacement, setup, and programming