S Klasse parking assist problem

I had a similar issue on my old Audi A6, though it was years ago. The parking assist just quit. Have you checked the radar sensors themselves? They can get gunked up, or the proximity sensors might be failing. Also, is the control module getting power? It might be worth a quick check before chasing wiring.

Where are the radar sensors located on this car? Are they easy to access without special tools?

On my A6, they were in the rear bumper, but it could be different on the S Klasse. Usually, you can access them by removing the bumper cover, which isn't too difficult. However, given the estimated cost, a workshop visit might be the best bet. They'll have the diagnostic tools to pinpoint the exact faulty wiring issue.

Thanks. I took it to the shop, and you were right. It was faulty wiring to one of the sensors. 95€ later, the parking assist is working again.