Diagnostic Procedure

The diagnostic procedures used in this system are designed to find and repair powertrain related problems. The general approach is to find the appropriate diagnosis for a problem with 5 basic steps described below.
1. Do you understand the customers complaint? The technician must understand what the customers complaint is. Failure to understand this may lead to misdiagnosis, or unnecessary diagnosis. Among other things, the technician must know whether the condition is present at all times, only under certain circumstances, or truly intermittent (random). This will assist the technician in duplicating and diagnosing the problem. Another reason the technician must understand the customers complaint is so the technician may determine whether the complaint requires service or is normal vehicle operation. Trying to diagnose a complaint that is normal will waste time and may result in unnecessary service.
2. Are Diagnostics working properly? Use the Powertrain On Board Diagnostic (OBD) System Check. This is the starting point for the diagnostic procedure, always begin here.
3. Are DTCs displayed? If a DTC is identified by diagnostics, the Powertrain On Board Diagnostic (OBD) System Check will direct you to the appropriate table.
4. Is the customers complaint related to a specific powertrain subsystem? If no related DTCs are set, the next quickest way to locate the problem is to narrow the problem down to a specific powertrain subsystem. If a specific subsystem can be pinpointed as the cause, the problem is easier to diagnose.
5. Is the problem powertrain related? Some customer complaints may appear to be powertrain related but are actually caused by other vehicle systems.