Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System
Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an
overview of the diagnostic approach.
* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure
Instructions) provides an overview of each diagnostic category.
DTC Descriptor
DTC B2580 00
- Headlamp High Beam Control Circuit
Diagnostic Fault Information
Circuit/System Description
When the turn signal/multifunction switch is placed in the headlamps high or flash to pass (FTP) position, ground is applied to the body control
module (BCM) through the headlamp high beam signal circuit or the flash to pass signal circuit. The BCM applies ground to the headlamp HIGH
BEAM relay control circuit which energizes the HIGH BEAM relay. With the HIGH BEAM relay energized, the switch contacts close allowing B+
to flow through the HI BEAM fuses to the high beam headlamps.
Conditions for Running the DTC
* Battery voltage must be between 9-16 V.
* Headlamps ON.
Conditions for Setting the DTC
The BCM detects a short to voltage in the headlamp HIGH BEAM relay control circuit.
Actions Taken When the DTC Sets
The high beam headlamps and flash to pass (FTP) 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
Headlights/Daytime Running Lights (DRL) Schematics (See: Diagrams/Electrical Diagrams/Lighting and Horns/System
