Symptom Related Diagnostic Procedures: Diagnosis and Testing

DIAGNOSIS AND TESTING - POWER STEERING SYSTEM
There is some noise in all power steering systems. One of the most common is a hissing sound evident at a standstill/parking, or when the steering is at the end of it's travel. Hiss is a high frequency noise similar to that of a water tap being closed slowly. The noise is present in all valves that have a high velocity fluid passing through an orifice. There is no relationship between this noise and steering performance.