Diagnostic Procedure

DIAGNOSTIC PROCEDURE USE
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 five basic steps described below.
1. Understand the customers complaint. It is critical that the technician 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 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 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 it down to a specific powertrain subsystem. If a specific subsystem can be pinpointed as the cause, it 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.