|  |  | Results of the tests | 
| 0 | PRELIMINARY CHECKS | All OK | Problems met | Operation | 
|---|
|  | tyre
inflation pressuretyre wear | Continue to Step 1 | Pressure not correct | Restore the pressure | 
| Tyres worn | Replace the tyres | 
| 1 | ROAD TEST | All OK | Problems met | Operation | 
|---|
|  | Road
test the vehicle on a straight, flat road increasing the speed until
the fault occurs.Steer gently to the left and the right keeping the speed constant | Continue to Step 2 | There are changes in the noise | Replace the wheel hub bearing
on the side the noise is coming from | 
| There are no changes in the noise | See table   S20  GEARBOX DIFFERENTIAL UNIT NOISY'/ | 
| 2 | CORRECT OPERATION CHECK | All OK | Problems met | Operation | 
|---|
|  | Check
that the fault is no longer present |  | Fault persists | Search for the fault starting from another symptom' |