DESCRIPTION AND OPERATION
Noise, Vibration and Harshness (NVH)
Acceptable NVH
Glossary of Terms
DIAGNOSIS AND TESTING
Diagnostic Theory
Diagnostic Procedure Overview
Tools and Techniques
Write-Up Job Aid
1: Customer Interview
2: Pre-Drive Check
3: Preparing for the Road Test
4: Verify the Customer Concern
5: Road Test
Slow Acceleration Test
Heavy Acceleration Test
Neutral Coast Down Speed Test
Downshift Speed Test
Steering Input Test
Brake Test
Road Test Over Bumps
Neutral Engine Run-Up (NERU) Test
Drive Engine Run-Up (DERU) Load Test
Engine Accessory Test
Vehicle Cold Soak Procedure
Classify NVH Symptom
Noise Symptoms
Vibration Symptoms
Order of Vibration
Relationship of Vibration Frequency to Order of Vibration
Frequency Calculations
Calculating Tire and Wheel Frequency
Calculating Driveshaft Frequency
Calculating Engine Frequency
Calculating Engine Accessory Frequency
Calculating Engine Firing Frequency
Frequency and RPM Calculations Worksheet
Harshness Symptoms
NVH Symptom Chart Categories
Vehicle-Speed Related Vibrations
Symptom Chart — Tire-Speed Related Vibrations
Symptom Chart — Driveshaft-Speed Related Vibrations
Symptom Chart — Engine-Speed Related Vibrations
Symptom Chart — Noise, Air Leaks or Water Leaks
Symptom Chart — Harshness
