Flow of Diagnosis

Flow of Diagnosis:

1. Complete VEHICLE REPAIR HISTORY and DRIVEABILITY WORKSHEET. Get a detailed description of the complaint. Verify condition by road testing if necessary.

NOTE: Vehicle Repair History and the Driveability Worksheets are located under Info Type, Technical/Management Support.

2. Perform underhood inspection, checking the following:

^ Vacuum hoses for proper routing, tight connections, splits, kinks and foreign obstacles (BB).

NOTE: Some vehicle manufacturers use an orifice-insert within a vacuum line as a delay device. Do NOT mistake as a BB and cut the vacuum line.

^ Vacuum fittings for improperly capped or plugged ports. Be sure to check the throttle body area, also.
^ Electrical and ignition wires for proper routing, cracking, hardness and tight connections at both the distributor and the spark plugs, kinks, and abrasions. Ground connections should be clean and tight.
^ Verify that all components are properly installed and have not been modified or damaged.
^ Check for air or vacuum leaks around the intake and exhaust manifolds, as well as the throttle body.
^ The catalytic converter(s), muffler, exhaust pipes, brackets, and hangers for modifications or damage.

3. Check TSB'S for manual updates, testing procedures, warranty and recall information.
4. If all checks are OK and a problem still exists, refer to Diagnostic Charts-Pinpoint Tests under Procedures. If symptom still exists after repairing any problems found in Pinpoint Tests, refer to Diagnosis By Symptom.