B2585

DTC B2585

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 B2585 00
- Left Parklamp Control Circuit

Diagnostic Fault Information





Circuit/System Description

Battery positive voltage is supplied to the PRK LAMP relay at all times. The body control module (BCM) grounds the park lamp relay control circuit in order to activate the relay. With the park lamp relay activated, voltage is supplied to the park lamp control circuit illuminating the park lamps, license lamps, and marker lamps.

Conditions for Running the DTC

* The ignition switch is in the RUN position.
* The ambient light sensor senses a dark condition, automatic lamp control (ALC) park lamps ON, or the headlamp switch is in the park or head ON position.

Conditions for Setting the DTC

The park lamp control circuit is shorted to voltage.

Action Taken When the DTC Sets

The park lamps are inoperative.

Conditions for Clearing the DTC

100 consecutive ignition cycles have been recorded without the DTC being detected.

Reference Information
Schematic Reference

Exterior Lights 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 Park Lamps ON and OFF with a scan tool. The park lamps should turn ON and OFF as commanded.

Circuit/System Testing

Before beginning this circuit/system test, review the schematic to verify:

* Park lights the vehicle is equipped with.
* Component locations on the park lighting control circuit
* Each component's control and ground circuit terminals

1. Ignition OFF, disconnect the PRK LAMP 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 an inoperative park lamp.
6. Test for less than 5 ohm between the ground circuit terminal and ground.

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

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

• If the park lamp 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 park lamp.
• If the park lamp 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 park lamp.

9. Connect a test lamp between the B+ circuit terminal 85 and the control circuit terminal 86.
10. Command the Park 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.

11. If all circuits test normal, test or replace the PRK LAMP relay.

Repair Instructions

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

* Relay Replacement (Attached to Wire Harness) (Service and Repair)
* Parking and Turn Signal Lamp Replacement (Traverse) (Service and Repair)
* Control Module References (Programming and Relearning) for BCM replacement, setup, and programming