Diagnostic Procedures

1: Customer Interview
It is important to interview the customer. Customer feedback can supply information that could be helpful in diagnosing the concern. Ask questions like:
- When is the concern present (at idle or while driving)?
- Where does the concern appear to be coming from?
- How long has the concern been there? Has it steadily become worse?
- When did the concern start?
- Does the concern change with engine speed or with vehicle speed?

Use the customer concern evaluation form, shown following the last step of this procedure, to record customer concerns.

2: Duplicate the Noise Concern
Is the noise heard while bouncing the bumper of the vehicle, driving over rough road surfaces, braking, when driving, or while parked?

Typically, front underbody noise is heard while doing the static bounce test (bouncing the bumper or the vehicle). If the noise can not be duplicated with the static bounce test, or during low speed turning maneuvers, it is most likely not suspension related.

3: Isolate the Noise Concern
If the noise can be duplicated by the static bounce test, one of the following methods will help to locate the problem while doing the static bounce test.
- Use a stethoscope or ChassisEAR to determine the area of the chassis that the noise appears to be coming from.
- Place your hand on the coil spring, radius arm, or stabilizer bar. This method is sometimes misleading as the vibrations may carry from one suspension component to another.

4: Inspecting the Vehicle
While inspecting the vehicle in the general area of the source of the noise, look for the following:
- loose fasteners
- worn/broken parts
- excessive dirt/rust accumulation
- signs of leaking fluid
- debris wrapped around the driveshaft, halfshaft or axle

5: Repair of the Vehicle
Use the symptom chart to find which pinpoint test and actions. Also, check TSBs, OASIS/Hotline for recent techniques or known related systems concerns.

6: Test Drive the Vehicle
Repeat the method used to duplicate the problem to verify that the noise has been repaired.

7: Follow Up with the Customer
Follow up with the customer about two weeks after the repair is performed to ensure that the noise was correctly identified and repaired.