B2590

DTC B2590

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 Descriptor
DTC B2590 00
- Left Cornering Lamp Circuit




Diagnostic Fault Information






Circuit/System Description

Battery positive voltage is applied at all times to both the coil and switched sides of the left and right PARK LAMP relays. 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 left and right park lamp relay control circuits. This energizes the left and right PARK LAMP relays and applies battery positive voltage to all of the park, tail, license, and marker lamps.


Conditions for Running the DTC

Battery voltage must be between 9-16 volts.


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.


Actions 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.
* You issue a scan tool CLEAR DTCs command.
* 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)


Circuit/System Testing

1. Ignition OFF, disconnect the left park lamp relay.
2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal R21 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 left 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 left cornering 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 left park lamp relay.



Repair Instructions

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

* Relay Replacement (Attached to Wire Harness) (Relay Replacement (Attached to Wire Harness))Relay Replacement (Within an Electrical Center) (Relay Replacement (Within an Electrical Center))
* Control Module References (Programming and Relearning)for BCM replacement, setup, and programming