DTC B2578: Headlamp Control Circuit High: Description

BCM controls headlamp relay located behind glove box, mounted to cross-car beam. BCM grounds headlamp relay control circuit which in turn energizes the headlamp relay to turn on the headlamps. DTC B2578 will be stored in memory if BCM detects a short to battery voltage in control circuit for more than 0.3 second when it is commanding the headlamp relay to energize. SERVICE VEHICLE SOON light will be illuminated when this code is stored in memory.

A current DTC B2578 will clear if short to battery voltage in control circuit is no longer detected by BCM. A history code B2578 will clear after 100 consecutive ignition cycles if conditions for setting DTC are no longer present. A scan tool may be used to clear DTC B2578.