General System Diagnosis

Perform the System Check Diagnostic System Check and refer to the Symptom Table. [1][2]Symptom Related Diagnostic Procedures Refer to Computer System Diagnosis for the appropriate diagnostic procedures. Computers and Control Systems

Important
^ Do NOT replace the Body Function Controller (BFC) unless a Diagnostic Trouble Code (DTC) remains Current after all DTC tables have been executed. NEVER replace the BFC based on History codes.
^ The BFC is connected to the Class 2 serial data link and is capable of setting Diagnostic Trouble Codes. The history DTC codes (a history DTC code is a fault that disappears in the next ignition cycle) can be especially useful in diagnosing an intermittent problem.

For a complete list of Diagnostic Trouble Codes refer to Body Control Module. Body Control Module