On-Board Diagnostic System Check: Notes

On-Board Diagnostic System Check is an organized approach for identifying a computer-controlled electronics problem. Understanding this check and using it correctly will reduce diagnostic time and prevent unnecessary replacement of parts.

If diagnostic system is not functional, a problem may be present in related system. Serial data line is connected between all computer systems and diagnostic system may have detected a problem in the serial data line. Scan tool will not be able to communicate.

Diagnose all present DTCs in the numerical order shown for system with fault. If no DTCs are present, check appropriate system which is exhibiting problem condition.