How to Use The Diagnostic Procedure

Noise, vibration and harshness is becoming more important as vehicles become more sensitive to vibrations. This is designed to give a working knowledge of the process of diagnosing noise and vibration situations. It is divided into several procedures based on the description of the condition. If the condition occurs at high speed for instance, the most likely place to start is under high speed shake. The road test procedures will tell how to sort out the conditions into categories and how to tell a vibration from a shake. It will give a few hints on quick checks to ensure that a cause is either pinpointed or eliminated.

Become familiar with the terms. Use the glossary to find the descriptive name of conditions not encountered before. After locating the name of the condition, proceed to identifying the condition, and the proper diagnosis procedure. By following these steps, most other systems in the vehicle have been eliminated. When the proper diagnostic procedure is identified, the job is partly done. Always follow each step exactly, and make notes along the way to recall important findings later.