How to Use The Diagnostic Procedure

- Noise, Vibration and Harshness (NVH) concerns have become more important as vehicles have become more sensitive to these vibrations. This information is designed to aid in identifying these situations.
- The diagnostic procedures are based on symptom. If the condition occurs at high speed, for instance, the most likely place to start is under High Speed Shake in the Symptom Chart.
- The Road Test procedure details how to sort the conditions into categories and distinguish a vibration from a shake.
- Following the Road Test procedure, a series of Road Test Quick Checks is provided to make sure that a cause is either pinpointed or eliminated.
- Use the Vehicle Road Test Evaluation Form following the Road Test procedure steps, to record road test results.
- Refer to the Glossary of Terms to become familiar with the terms.
- Name the condition, go to the system and locate the proper diagnosis. When the condition is identified, the job is partly done.
- Follow the diagnostic procedure.
- Follow the steps.
- Quick checks are described within the step, while more involved tests and adjustments are found in the Service Procedures and in the Adjustments.
- Always follow each step exactly and make notes along the way to recall important findings.