B2580

DTC B2580

DTC DESCRIPTOR

DTC B2580 00
Headlamp High Beam Control Circuit

DIAGNOSTIC FAULT INFORMATION




Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview

CIRCUIT/SYSTEM DESCRIPTION
Voltage is applied at all times to the high beam headlamp relay from battery voltage. When the multifunction switch is placed in either the FTP or HIGH position, ground is applied to the body control module (BCM). The BCM then applies a ground to the headlamp high beam relay control circuit. This engages the relay and applies voltage through the HI HEADLAMP fuses to both left and right high beam headlamps.

CONDITIONS FOR RUNNING THE DTC
- The headlamps are commanded ON.
- Headlamp dimmer switch must be in the high beam position.

CONDITIONS FOR SETTING THE DTC
The BCM detects a short to voltage on the headlamp high beam relay control circuit.

ACTION TAKEN WHEN THE DTC SETS
The high beam headlamps are inoperative.

CONDITIONS FOR CLEARING THE DTC
- The conditions for setting the DTC are no longer present.
- A history DTC clears after 100 malfunction-free ignition cycles.
- The BCM receives the clear code command from the scan tool.

CIRCUIT/SYSTEM VERIFICATION
Ignition ON, activate the High Beam output control on the scan tool. The High Beam Relay Command parameter in the data list should display On and the high beam headlamps should illuminate.

CIRCUIT/SYSTEM TESTING
1. Ignition OFF, disconnect the BCM connector C4.
2. Ignition ON, test for voltage at the BCM harness connector terminal 16.
- If voltage is present, test the control circuit for a short to voltage. If all circuits/connections test normal, replace the underhood fuse block.
- If voltage is not present, replace the BCM.

REPAIR INSTRUCTIONS
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
- Underhood Electrical Center or Junction Block Replacement
- Control Module References for BCM replacement, setup, and programming. Verification Tests Programming and Relearning