- How to Use This Section

1. Following a Flow of Diagnosis will usually lead to the correct test procedure and help repair the problem.

2. The "OBD Diagnostic Circuit Check" under Computers and Control Systems/System Diagnosis/Procedures* should ALWAYS be performed whether or not a computer related problem is suspected. The "OBD Diagnostic Circuit Check" may reveal computer problems which were not originally suspected. Bypassing this test during diagnosis may lead to replacement of good parts.
Testing and Inspection

3. If test procedures cannot fix the problem (or is not available), you can find additional component and system information in these areas:

- Component Test Charts Information and tests for various components and sub-systems. Testing and Inspection

- Trouble Code Diagnostic Charts under Computers and Control Systems/System Diagnosis/Procedures - may be reviewed for diagnostic notes and circuit descriptions.
Testing and Inspection

CAUTION: Trouble Code charts should Never be used to diagnose a component unless that trouble code has been stored. Using the trouble code chart without a stored trouble code may lead to incorrect diagnosis and replacement of good parts.

- Diagnosis by Symptoms - under Computers and Control Systems/System Diagnosis/Procedures should be used when no computer related problems appear. Refer to the related system (Computers and Control Systems, Fuel Control Systems, Ignition Control System, etc.)
Testing and Inspection

- System or Component Descriptions - Sometimes getting a better idea of HOW the system or component works can help with diagnosis of a problem.