Diagnostic Aids
WARNING: This page is about a different car, the 2003 Buick Regal and 2003 Buick Century. However, it is still accessible from the selected car via links, so may be relevant.
- If the DTC B2578 is a history DTC, the fault may be intermittent. Refer to TESTING FOR INTERMITTENT AND POOR CONNECTIONS in Wiring Systems.
- The following conditions may cause an intermittent malfunction to occur:
- An intermittent short to battery in the automatic autolamp relay coil control circuit.
- The automatic autolamp relay coil is intermittently shorted to battery.
- The BCM is intermittently shorted to battery.