B2605

DTC B2605

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 B2605 02
- Right Daytime Running Lamps Control Circuit Short to Ground

Diagnostic Fault Information





Circuit/System Description

When the headlight switch is placed in low beam position, the body control module (BCM) applies a voltage to the head lamps through there respective voltage supply circuits.

Conditions for Running the DTC

The engine is running, headlamp switch in AUTO position, and the ambient light is day.

Conditions for Setting the DTC

The BCM detects a short to ground on the control circuit.

Action Taken When the DTC Sets

The right daytime running lamp is inoperative.

Conditions for Clearing the DTC

The condition responsible for setting the DTC no longer exists.

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, command the Low Beam Relay Command ON and OFF with a scan tool. The low beam headlamp should turn ON and OFF when changing between the commanded states.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the E4H Headlamp-Right Low Beam.
2. Test for less than 5 ohm between the E4H Headlamp-Right Low Beam ground circuit terminal B and ground.

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

3. Connect a test lamp between the E4H Headlamp-Right Low Beam control circuit terminal A and ground.
4. Command the Low Beam Relay Command 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 signal circuit for a short to voltage. If the circuit tests normal, replace the K9 BCM.
• If the test lamp is always OFF, test the Signal circuit for a short to ground or an open/high resistance. If the circuits test normal, replace the K9 BCM.

5. If all the circuits test normal, replace the E4H Headlamp-Right Low Beam.

Repair Instructions

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

* Headlamp Replacement (Equinox) (Service and Repair)Headlamp Replacement (Terrain) (Service and Repair)
* Control Module References (Programming and Relearning) for headlamp control module and BCM replacement, setup, and programming