Mercedes M Klasse parking aid malfunction

I've seen similar parking assistance malfunctions, but not specifically on an M Klasse. Often, the radar sensors are the problem, not the wiring. Have you checked the sensors for damage or obstructions? Are they all clean? Even a little dirt can interfere. Does the error appear immediately, or only after trying to use the parking aid?

I've visually inspected the parking sensors; they look clean and undamaged. The error is there from the start. If the radar sensors are faulty, can I identify the specific sensor without special equipment?

A visual check is a good start, but not definitive. Finding the faulty sensor usually needs diagnostic equipment to test each sensor's response. Since the error is immediate and you've checked the basics, I'd suggest a workshop does a diagnostic assessment. It's the best way to find the fault. The repair should be around 95€, which is reasonable.

Thanks for the advice. I had it professionally diagnosed. It was a corroded connector on a proximity sensor, as suspected. The repair went as expected.