B2585

DTC B2585

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC B2585 00
- Park Lamp Control Circuit

Diagnostic Fault Information






Circuit/System Description

Voltage is applied at all times to the park lamp relay from battery voltage. When the headlamp switch is placed in the PARK position and the body control module (BCM) commands the park lamps ON, the BCM then applies a ground to the park lamp relay control circuit. This engages the relay and applies voltage through the park lamp fuses and to all the park, license, and tail lamps.

Conditions for Running the DTC

* The Ignition is ON.
* The park lamps must be commanded ON by the BCM.

Conditions for Setting the DTC

The BCM detects a short to voltage on the park lamp relay control circuit.

Action Taken When the DTC Sets

All park, license, and tail lamps are inoperative.

Conditions for Clearing the DTC

* The conditions for setting the DTC are no longer present.
* A history DTC clears after 100 malfunction-free ignition cycles.
* The BCM receives the clear code command from the scan tool.

Circuit/System Verification

Ignition ON, activate the Parking Lamp output control on the scan tool. The Park Lamp Relay Command parameter in the data list should display On and the park lamps should illuminate.

Circuit/System Testing

1. Ignition OFF, disconnect the park lamp relay.
2. Connect a test lamp between the relay control circuit terminal 85 and the B+ circuit terminal 86.
3. Command the parking 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 relay control circuit for a short to ground. If the circuit tests normal, replace the BCM.

^ If the test lamp is always OFF, test the relay control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.

4. If all circuits test normal, test or replace the park lamp relay.

Repair Instructions

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

* Relay Replacement (Attached to Wire Harness) Relay Replacement (Within an Electrical Center)