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

Battery positive voltage is applied at all times to both the coil and switched sides of the PARK LAMP relay. Ground is applied from G200 to the multifunction switch at all times. When the headlamp switch is placed in either the HEAD or PARK position, ground is applied to the park lamp relay control circuit. This energizes the PARK LAMP relay and applies battery positive voltage to all of the park, tail, license, and marker lamps. For more detailed information concerning park lamp operation refer to Exterior Lighting Systems Description and Operation.

Conditions for Running the DTC

Battery voltage must be between 9-16 volts.

Conditions for Setting the DTC

DTC B2585 00 will set when the BCM detects a short to voltage in the park lamp relay control circuit.

Actions Taken When the DTC Sets

When DTC B2585 00 is present, the park lamps will not operate.

Conditions for Clearing the DTC

* The condition responsible for setting the DTC no longer exists.
* You issue a scan tool CLEAR DTCs command.
* A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Circuit/System Testing

1. Ignition OFF, disconnect the park lamp relay.
2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal R23 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 R25 and ground.

• If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the control circuit terminal R23 for a short to ground. If the circuit tests normal, test or replace the park lamp relay.

4. Verify that a test lamp illuminates between the B+ circuit terminal R22 and ground.

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

5. Connect a test lamp between the B+ circuit terminal R25 and the control circuit terminal R21.
6. Command the parks 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.

7. 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 (Within an Electrical Center)
* Control Module References for BCM replacement, setup, and programming. Programming and Relearning