B2590

DTC B2590

Diagnostic Instructions

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

DTC Descriptor
DTC B2590 00
- Left Cornering Lamp Control Circuit

Diagnostic Fault Information





Circuit/System Description

Battery voltage is applied at all times to the left front cornering lamp PCB relay which is part of the underhood fuse block. When the turn signal switch is placed in the left turn position, ground is applied through the left turn signal switch signal circuit to the body control module (BCM) The BCM then applies a ground to the left cornering lamp relay control circuit energizing the relay. With the relay energized, battery voltage is applied through the switch side of the relay, the LF CRN LAMP Fuse, and the left front cornering lamp supply voltage circuit to the left front cornering lamp.

Conditions for Running the DTC

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

Conditions for Setting the DTC

DTC B2590 00 will set when the BCM detects a short to voltage in the left cornering lamp relay control circuit.

Action Taken When the DTC Sets

When DTC B2590 00 is present, the left cornering lamps will not operate.

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 (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing For Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)

Scan Tool Reference

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

Circuit/System Testing

1. Ignition OFF, disconnect the X2 harness connector at the underhood fuse block.
2. Connect a test lamp between B+ and the control circuit terminal K1.
3. Ignition ON, command the Left Cornering Lamp 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.

4. If the circuit tests normal, replace the underhood fuse block.

Repair Instructions

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

* Underhood Electrical Center or Junction Block Replacement (Removal and Replacement)
* Control Module References (Programming and Relearning) for BCM replacement, setup, and programming