- Diagnostic Procedure
DIAGNOSTIC PROCEDURESThese diagnostic procedures are designed to find and repair Engine related problems. The general approach is to find the appropriate diagnosis for a problem by using the basic steps described below.
Understand the customer's complaint
It is critical that the technician understands what the customer's 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 customer's 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.
Are the Diagnostics working properly?
Use the Powertrain OBD System Check. This is the starting point for all of the diagnostic procedures. Always begin here: Testing and Inspection
Are the DTCs displayed?
If a DTC is identified by the diagnostics, the Powertrain OBD System Check will direct you to the appropriate chart within Engine System Diagnosis.
Is the complaint related to a specific subsystem?
If no related DTCs are set, the next quickest way to locate the problem is to narrow the problem down to a specific engine subsystem. If a specific subsystem can be pinpointed as the cause, the problem will be easier to diagnose. Tests for some sub-systems are located at the Diagnostic Tables section of Computers and Controls / System Diagnostics / Procedures. Testing and Inspection