Diagnosis of engine performance or drivability problems on a vehicle with an onboard computer requires that you have a logical plan on how to approach the problem. The Six Step Test Procedure is designed to provide a uniform approach to repair any problems that occur in one or more of the vehicle subsystems.The diagnostic flow built into this test procedure has been field-tested for several years at dealerships - it is the starting point when a repair is required!
It should be noted that a commonly overlooked part of the Problem Resolution step is to check for any related Technical Service Bulletins.
Six-Step Test Procedure
The steps outlined on this page were defined to help you determine how to perform a proper diagnosis. Refer to the flow chart that outlines the Six Step Test Procedure on the previous page as needed. The recommended steps include: