B2580

DTC B2580

DTC DESCRIPTOR

DTC B2580 01
Headlamp High Beam Control Circuit Short to Voltage

DTC B2580 06
Headlamp High Beam Control Circuit Open or Short to Ground




DIAGNOSTIC FAULT INFORMATION

IMPORTANT: Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Testing and Inspection

CIRCUIT/SYSTEM DESCRIPTION
With the headlamp switch in the HEAD position, the headlamp switch headlamp ON signal circuit is grounded through the turn signal/multifunction switch at G201. In response to this input, the body control module (BCM) provides ground to either the headlamp low beam relay control circuit through the headlamp switch signal circuit or the headlamp high beam relay control circuit. The position of the headlamp dimmer switch determines which relay coil has ground. The BCM supplies ground to the relay coil circuits, if the headlamps are necessary. The underhood fuse block supplies battery positive voltage to both relay switch circuits. When the low beam relay coil is energized, current flows through the LH LOW beam and the RH LOW beam fuses to the low beam headlamps. When the headlamp high beam relay coil is energized, current flows through the LH HI beam and the RH HI beam fuses to the high beam headlamps. Ground for the left headlamp assembly is provided at G101. Ground for the right headlamp assembly is provided at G102.

CONDITIONS FOR RUNNING THE DTC
Battery voltage must be between 9-16 volts.

CONDITIONS FOR SETTING THE DTC

DTC B2580 01
This DTC will set when the BCM detects a short to battery voltage in the headlamp high beam relay control circuit.

DTC B2580 06
This DTC will set when the BCM detects an open or short to ground in the headlamp high beam relay control circuit.

ACTION TAKEN WHEN THE DTC SETS
- When DTC B2580 01 is present, the high beam headlamps will not operate.
- When DTC B2580 06 is present, the high beam headlamps will remain ON.

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.

CIRCUIT/SYSTEM TESTING

DTC B2580 01
1. Ignition OFF, disconnect the high beam relay.
2. Ignition ON, turn OFF the high beam headlamps.
3. Verify that a test lamp does not illuminate between the headlamp high beam relay control circuit and ground at the high beam relay terminals.
- If the test lamp illuminates, repair the headlamp high beam relay control circuit for a short to battery voltage. If the circuit tests normal, replace the BCM.
4. If all circuits test normal, test or replace the high beam relay.

DTC B2580 06
1. Ignition OFF, disconnect the high beam relay.
2. Turn OFF the high beam headlamps.
3. Verify that a test lamp does not illuminate between the high beam relay battery voltage supply circuit and the high beam relay control circuit at the high beam relay terminals.
- If the test lamp illuminates, repair the headlamp high beam relay control circuit for a short to ground. If the circuit tests normal, replace the BCM.
4. Ignition ON, turn ON the high beam headlamps.
5. Verify that a test lamp illuminates between the high beam relay battery voltage supply circuit and the high beam relay control circuit at the high beam relay terminals.
- If the test lamp does not illuminate, repair the headlamp high beam relay control circuit for an open/high resistance. If the circuit tests normal, replace the BCM.
6. If all circuits test normal, test or replace the high beam relay.

REPAIR INSTRUCTIONS

IMPORTANT: Always perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

- Underhood Electrical Center or Junction Block Replacement
- Relay Replacement (Within an Electrical Center) Relay Replacement (Attached to Wire Harness)
- Control Module References for BCM replacement, setup and programming