Diagnostic Procedure

7: Diagnostic Procedure
Qualifying the concern by the particular sensation present can help narrow down the concern. Always use the symptom to system to component to cause diagnosis technique. This diagnostic method divides the problem into related areas to correct the customer concern.
^ Verify the symptom.
^ Determine which system(s) can cause the symptom.
^ If a vibration concern is vehicle speed-related, the tire and wheel rpm/frequency or driveshaft frequency should be calculated.
^ If a vibration concern is engine speed-related, the engine, engine accessory or engine firing frequencies should be calculated.
^ After determining the system, use the diagnostic tools to identify the worn or damaged components.
^ After identifying the components, try to find the cause of the failure.
Once the concern is narrowed down to a symptom/condition, proceed to NVH Condition and Symptom Categories.