Buick Regal: DTC B2590 or B2595

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 B2590 00

Left Cornering Lamp Circuit Malfunction

DTC B2590 54

Left Cornering Lamp Circuit High Temperature

DTC B2595 00

Right Cornering Lamp Circuit Malfunction

DTC B2595 54

Right Cornering Lamp Circuit High Temperature

Circuit/System Description

The cornering lamps are activated automatically at vehicle speeds below 40 km/h (25 MPH) when the turn signal/multifunction switch is placed in either the turn left or turn right positions and/or when the steering angle is changed from the straight-ahead position towards the side the vehicle is turning. When the headlamp control module detects that one of these operations has occurred, the headlamp control module sends a message via serial data to the left or right headlamp/cornering lamp control module. The appropriate headlamp/cornering lamp control module responds by applying battery voltage to the appropriate cornering lamp LED to illuminate the area that the vehicle is turning. The cornering lamps are deactivated automatically when the turn signal/multifunction switch is placed in the neutral position and/or the steering angle has returned in the straight-ahead position. The cornering lamps will not operate at vehicle speeds above 40 km/h (25 MPH).

Conditions for Running the DTC

• Battery voltage must be between 9 - 16 V.
• Ignition ON.
• Front fog lamps OFF.
• Cornering lamps ON.

Conditions for Setting the DTC

DTC B2590 00

The headlamp/cornering lamp control module - left detects an internal malfunction in the left cornering lamp circuit.

DTC B2590 54

The headlamp/cornering lamp control module - left detects an invalid temperature in the left cornering lamp circuit.

DTC B2595 00

The headlamp/cornering lamp control module - right detects an internal malfunction in the right cornering lamp circuit.

DTC B2595 54

The headlamp/cornering lamp control module - right detects an invalid temperature in the right cornering lamp circuit.

Actions Taken When the DTC Sets

• One or more cornering lamp LEDs are inoperative.
• The driver information center will display "Advanced Front Lighting System Fault."

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

DTC B2590 or B2595 will set when one or more of the cornering lamp LED's contained within the headlamp assembly are inoperative. The following components are serviceable within the headlamp assembly.

• 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

Headlights/Daytime Running Lights (DRL) 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 Verification

1. Ignition ON.

2. Verify DTC B2590 or B2595 is not set.

• If DTC B2590 or B2595 is set

1. Replace the appropriate K189 Headlamp/Cornering Lamp Control Module.
2. Verify DTC B2590 or B2595 is not set.

• If DTC B2590 or B2595 is set

3. Replace the appropriate E13 Headlamp Assembly.

• Go to next step: If DTC B2590 or B2595 is not set

3. All OK

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

• Headlamp Replacement
• Headlamp LED Driver Module Replacement
• Control Module References for Headlamp/Cornering Lamp Control Module replacement, programming, and setup

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