Diagnostic Theory

The shortest route to an accurate diagnosis results from:

^ system knowledge, including comparison with a known good system.

^ system history, including repair history and usage patterns.

^ condition history, especially any relationship to repairs or sudden change.

^ knowledge of probable causes

^ using a systematic diagnostic method that divides the system into related areas.

The diagnosis and correction of noise, vibration and harshness concerns requires:

^ a road or system test to determine the exact nature of the concern.

^ an analysis of the possible causes.

^ testing to verify the cause.

^ repairing any concerns found.

^ a road test or system test to make sure the concern has been corrected or brought back to within a acceptable range.