Diagnostic Strategies

DIAGNOSIS OF FAULTS IS DONE IN FOUR BASIC STEPS:


1. Visual inspection


- A careful and thorough visual inspection may quickly identify the cause of a malfunction and eliminate the need for additional diagnostic procedures.

- Diagnosis of vehicle faults always starts with the visual inspection. If the fault is not resolved by the visual inspection, perform the Preliminary Check Procedure.


2. Preliminary Check Procedure


- Diagnosis should continue with the Preliminary Check Procedure. It is will help determine if a problem is mechanical or electrical. The first procedure step is Initial Inspection and Adjustment.

- If the fault is not resolved by the Preliminary Check Procedure, perform the Diagnostic tests in Diagnostic Charts.


3. Diagnostic tests


- Each specific fault is diagnosed by following a specific testing sequence. It is not necessary to perform all of the tests in this book to diagnose an individual fault.

- Always begin diagnostic testing with Test IA. This will direct you to the specific test(s) that must be performed in response to the specific vehicle fault.


4. Verification test

- A verification of system operation must always be performed to ensure that the system is operating normally after the cause of a fault has been found and repaired.