I have a problem with the speed sensitive power steering on my 406 v6 from 2000 (235 000 km).
The loss of power steering was gradual, and especially noticeable at low speed when trying to park. I am not sure, but the power steering seems to improve after 15-20 min of driving - and the fluid reservouir is filled.
I have tried to turn the wheel to full stop and listened after the power steering motor bypass, but it does not come with a high characteristic sound as on my friends v6 from '99. There seems to be a sound but it is high pitched low volume squeal.
There is no warning lights in the dashboard, but the car also appears to be leaking engine coolant, even though I think that the problem is not necessarily related.
I suspect that the power steering motor is defect, but perhaps you have some other thoughts or ways of troubleshooting the issue
