3: Preparing for the Road Test

Noise, Vibration and Harshness (NVH)

3: Preparing for the Road Test

Observe the following when preparing for the road test:

- Review the information recorded on the write-up job aid. It is important to know the specific symptom the customer has with the vehicle.
- Do not be misled by the reported location of the noise/vibration. The cause can actually be some distance away.
- Conduct the road test on a quiet street where it is safe to duplicate the vibration/noise. The ideal testing route is an open, low-traffic area where it is possible to operate the vehicle at the speed in which the condition occurs.
- While observing that they are not related to the symptom, eliminate the following:
- If possible, lower the radio antenna in order to minimize turbulence.
- Identify anything that could potentially make noise or be a source of wind noise.
- Inspect the vehicle for add-on items that create vibration/noise.
- Turn off the radio and the heating and cooling system blower.

- The engine speed is an important factor in arriving at a final conclusion. Therefore, connect a diagnostic tool, Vertronix, or an accurate tachometer to the engine, even if the vehicle has a tachometer. This will make sure of an exact engine speed reading.