Buick Regal: DTC B2585 or B3867

Diagnostic Instructions

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

DTC Descriptors

DTC B2585 02

Left Park Lamps Control Circuit Short to Ground

DTC B2585 04

Left Park Lamps Control Circuit Open

DTC B3867 02

Right Park Lamps Control Circuit Short to Ground

DTC B3867 04

Right Park Lamps Control Circuit Open

Diagnostic Fault Information

1. Park, License, and/or Tail Lamps Malfunction

Circuit/System Description

When the headlamp switch is placed in the HEAD or PARK position, ground is applied to the park lamp switch ON signal circuit to the body control module (BCM). The BCM responds by applying voltage to the park lamps, tail lamps, and license lamps control circuits illuminating the park, tail, and license lamps.

Conditions for Running the DTC

• Battery voltage must be between 9 - 16 V.
• Park lamps ON.

Conditions for Setting the DTC

DTC B2585 02

The BCM detects a short to ground in the left park lamps control circuit terminal 6 X4.

DTC B2585 04

The BCM detects an open/high resistance in the left park lamps control circuit terminal 6 X4.

DTC B3867 02

The BCM detects a short to ground in the right park lamps control circuit terminal 5 X4.

DTC B3867 04

The BCM detects an open/high resistance in the right park lamps control circuit terminal 5 X4.

Actions Taken When the DTC Sets

DTC B2585 02 and B2585 04

The left park lamps are always OFF.

DTC B3867 02 and B3867 04

The right park lamps are always OFF.

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.

Diagnostic Aids

The following control modules located on each headlamp assembly are serviceable.

• K189L Headlamp/Cornering Lamp Control Module - Left
• K189R Headlamp/Cornering Lamp Control Module - Right
• K26L Headlamp Control Module - Left
• K26R Headlamp Control Module - Right

Reference Information

Schematic Reference

Exterior Lights Wiring Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Exterior Lighting Systems Description and Operation

Electrical Information Reference

• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information.

Circuit/System Testing

DTC B2585

1. Ignition OFF, exterior lamps OFF, disconnect the harness connector at the appropriate component listed below. It may take up to 2 min for all vehicle systems to power down.

• E13LA Headlamp Assembly - Left
• E2LF Side Market Lamp - Left Front
• E42L Tail Lamp Assembly - Left
• E43L Liftgate Tail Lamp Assembly - Left

2. Test for less than 10 Ω between the appropriate ground circuit terminal listed below and ground.

• E13LA Headlamp Assembly - Left terminal 1 (with T4L)
• E13LA Headlamp Assembly - Left terminal 2 (with T4A)
• E2LF Side Market Lamp - Left Front terminal 2
• E42L Tail Lamp Assembly - Left terminal 4
• E43L Liftgate Tail Lamp Assembly - Left terminal 4
• If 10 Ω or greater

1. Ignition OFF.
2. Test for less than 2 Ω in the ground circuit end to end.
   • If 2 Ω or greater, repair the open/high resistance in the circuit.
   • If less than 2 Ω, repair the open/high resistance in the ground connection.

• Go to next step: If less than 10 Ω

3. Connect a test lamp between the appropriate control circuit terminal listed below and ground, ignition ON.

• E13LA Headlamp Assembly - Left terminal 4
• E2LF Side Market Lamp - Left Front terminal 1
• E42L Tail Lamp Assembly - Left terminal 1
• E43L Liftgate Tail Lamp Assembly - Left terminal 1

4. Verify the test lamp turns ON and OFF when commanding the Left Park Lamps ON and OFF with a scan tool.

• If the test lamp is always OFF

1. Ignition OFF, disconnect the X4 harness connector at the K9 Body Control Module.
2. Test for infinite resistance between the control circuit and ground.
   • If less than infinite resistance, repair the short to ground on the circuit.
   • Go to next step: If infinite resistance
3. Test for less than 2 Ω in the control circuit end to end.
   • If 2 Ω or greater, repair the open/high resistance in the circuit.
   • If less than 2 Ω, replace the K9 Body Control Module.

• If the test lamp is always ON

1. Ignition OFF, disconnect the X4 harness connector at the K9 Body Control Module, ignition ON.
2. Test for less than 1 V between the control circuit terminal and ground.
   • If 1 V or greater, repair the short to voltage on the circuit.
   • If less than 1 V, replace the K9 Body Control Module.

• Go to next step: If the test lamp turns ON and OFF

5. Test or replace the park lamp.

DTC B3867

1. Ignition OFF, exterior lamps OFF, disconnect the harness connector at the appropriate component listed below. It may take up to 2 min for all vehicle systems to power down.

• E13RA Headlamp Assembly - Right
• E2RF Side Market Lamp - Right Front
• E42R Tail Lamp Assembly - Right
• E43R Liftgate Tail Lamp Assembly - Right

2. Test for less than 10 Ω between the appropriate ground circuit terminal listed below and ground.

• E13RA Headlamp Assembly - Right terminal 1 (with T4L)
• E13RA Headlamp Assembly - Right terminal 2 (with T4A)
• E2RF Side Market Lamp - Right Front terminal 2
• E42R Tail Lamp Assembly - Right terminal 4
• E43R Liftgate Tail Lamp Assembly - Right terminal 4
• If 10 Ω or greater

1. Ignition OFF.
2. Test for less than 2 Ω in the ground circuit end to end.
   • If 2 Ω or greater, repair the open/high resistance in the circuit.
   • If less than 2 Ω, repair the open/high resistance in the ground connection.

• Go to next step: If less than 10 Ω

3. Connect a test lamp between the appropriate control circuit terminal listed below and ground, ignition ON.

• E13RA Headlamp Assembly - Right terminal 4
• E2RF Side Market Lamp - Right Front terminal 1
• E42R Tail Lamp Assembly - Right terminal 1
• E43R Liftgate Tail Lamp Assembly - Right terminal 1

4. Verify the test lamp turns ON and OFF when commanding the Right Park Lamps ON and OFF with a scan tool.

• If the test lamp is always OFF

1. Ignition OFF, disconnect the X4 harness connector at the K9 Body Control Module.
2. Test for infinite resistance between the control circuit and ground.
   • If less than infinite resistance, repair the short to ground on the circuit.
   • Go to next step: If infinite resistance
3. Test for less than 2 Ω in the control circuit end to end.
   • If 2 Ω or greater, repair the open/high resistance in the circuit.
   • If less than 2 Ω, replace the K9 Body Control Module.

• If the test lamp is always ON

1. Ignition OFF, disconnect the X4 harness connector at the K9 Body Control Module, ignition ON.
2. Test for less than 1 V between the control circuit terminal and ground.
   • If 1 V or greater, repair the short to voltage on the circuit.
   • If less than 1 V, replace the K9 Body Control Module.

• Go to next step: If the test lamp turns ON and OFF

5. Test or replace the park lamp.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

• Headlamp Replacement
• Rear License Plate Lamp Replacement
• Rear Body Structure Stop Lamp Replacement (5-Door Hatchback 68) Rear Body Structure
• Stop Lamp Replacement (5-Door Wagon 35)
• Tail Lamp Replacement (5-Door Hatchback 68) Tail Lamp Replacement (5-Door Wagon 35)
• Control Module References for BCM replacement, programming, and setup

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