Diagnostic Routines Preface

The Diagnostic Routines list in test step form the systems that can contribute to a particular condition in the order of probability, ease of accomplishment, and accessibility. These routines can be used as check lists for reference in the event of unusual or infrequent causes of a malfunction.


The order in which the diagnostic routines are listed has been carefully organized to include the most frequent faults at the top of each symptom list and least frequent at the bottom. In some cases a system is listed ahead of another due to the fact that it is much easier to diagnose and, therefore, less time consuming. Unless the fault is evident, it is recommended that all diagnosis begin with a thorough visual inspection of a suspected system or component, followed by a system by system diagnosis as presented in the following routines. After each repair is made, check to see if symptom(s) are still presented. If a particular system is determined to be operating normally, return to the Diagnostic Routine for other possible causes of the symptom.


SPECIAL NOTES:
The technician is not required to adhere to the order specified in the diagnostic routines due to variations in vehicle type, system accessibility, vehicle repair history or technician experience.

On-line Automotive Service Information System (OASIS) numbers have been included where applicable.

The technician should obtain OASIS special service information on the customer's concern prior to performing extensive diagnosis and repairs.


When referenced to another area, look at the visual inspection chart provided prior to the test procedure. These charts list obvious fault possibilities that may have been overlooked.

This section also contains a "Customer Information Worksheet." This worksheet is to be filled in by the customer so that his/her description of the problem can be given to the technician working on the vehicle. Customer Information Worksheet