B2585

DTC B2585 or B3867

Diagnostic Instructions

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

DTC Descriptors
DTC B2585 00
- Front Left Parking Lamp Circuit Malfunction

DTC B3867 00
- Front Right Parking Lamp Circuit Malfunction

Diagnostic Fault Information





Circuit/System Description

The headlamp switch is supplied with voltage from the instrument panel cluster (IPC) by two signal circuits, the headlamp signal circuit and the park lamp signal circuit. When the headlamp switch is placed in the PARK position, the park lamp signal circuit is provided with ground through the switch contacts of the park lamp switch to a common headlamp switch ground back to the IPC. The IPC interprets the flow of voltage and responds by sending a serial data message to the underhood electrical center (UEC) and the rear electrical center (REC) requesting the front and rear park lamps be activated. The UEC and REC respond by applying voltage to there respective park, marker, and license lamp control circuits illuminating the park, marker and license lamps.

Curb Side Parking Lamps

Curb side parking lamps is a feature that allows the vehicles owner to activate either the left or right side parks lamps while the vehicle is parked and the ignition is off. Curb side parking lamps is a European mandate and all vehicles sold in the United States will be programmed with it. This feature is software driven and cannot be changed or reprogrammed to illuminate it. To activate the curb side parking lamps the following conditions must be met:

1. Ignition OFF.
2. Turn signal switch placed in either the RIGHT or LEFT position.

When these conditions are met, the front and rear parking lamps for only the side selected will remain illuminated until the turn signal switch is placed in the neutral position or the ignition switch is cycled ON then OFF. This feature is not safe guarded by the vehicles battery rundown protection and in the event that the curb side parking feature is left ON, total battery discharge will occur. Upon activating the curb side parking lamps, an audible warning of three chimes will notify the vehicles owner that the feature is active.

Conditions for Running the DTC

* Battery voltage must be between 9-16 volts.
* Park lamps ON.

Conditions for Setting the DTC

B2585 00

The DTC will set when the UEC detects a short to ground or an open/high resistance in the left front park lamp control circuit.

B3867 00

The DTC will set when the UEC detects a short to ground or an open/high resistance in the right front park lamp control circuit.

Actions Taken When the DTC Sets

The UEC will disable the front park lamp control circuit that has a fault present.

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

Exterior Lights Schematics (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 (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the inoperative headlamp assembly.
2. Ignition OFF, exterior lamps OFF, test for less than 5.0 ohms between the ground circuit terminal 1 and ground.

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

3. Connect a test lamp between the control circuit terminal 4 and ground.
4. Command the Front Parking Light Test 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 voltage. If the circuit tests normal, replace the UEC.
• If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the UEC.

5. If all circuits test normal, replace the inoperative parking lamp.

Repair Instructions

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

* Headlamp Bulb Replacement (without High Intensity) (Service and Repair)
* Control Module References (Programming and Relearning) for UEC replacement, setup, and programming