B2578

DTC B2578

CIRCUIT DESCRIPTION
The body control module (BCM) controls the headlamp relay. The BCM grounds the headlamp relay coil control circuit, which energizes the headlamp relay.

CONDITIONS FOR RUNNING THE DTC
The BCM must be commanding the headlamp relay to energize.

CONDITIONS FOR SETTING THE DTC
- The BCM detects a short to battery in the headlamp coil control circuit when the BCM tries to energize the headlamp relay.
- The condition above must be present for more than 0.3 seconds.

ACTION TAKEN WHEN THE DTC SETS
The BCM stores DTC B2578 in memory.

CONDITIONS FOR CLEARING THE DTC
- A current DTC B2578 will clear if the BCM no longer detects a short to battery in the headlamp relay coil control circuit.
- A history DTC B2578 will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present.

DIAGNOSTIC AIDS
- If the DTC B2578 is a history DTC, the fault may be intermittent.
- The following conditions may cause an intermittent malfunction to occur:
- An intermittent short to battery in the headlamp relay coil control circuit.
- The headlamp relay coil is intermittently shorted to battery internally.
- The BCM is intermittently shorted to battery internally.

TEST

Steps 1 - 7:

Steps 8 - 13: