E Class sensors

[.richard]

2013 E Class now owned for four years. When I bought the car from Mercedes the sensors both front and rear would go AWOL. Only about 5% of time. Switched off ignition and back on. Sensors would work. Went into Mercedes three times under warranty but couldn’t find a fault. I don’t blame them in anyway. It would go days reversing itself into the smallest gaps. How can you give a garage a fault which isn’t there for weeks?
When fault occurs front and rear sensors are illuminated but don’t show any close proximity. Very rarely they don’t even illuminate.
In my limited knowledge it is not an in individual sensor. System has been into Merc and no problem found. Apparently also rebooted. Personally I would go for a multi plug. Any help appreciated.

[CJ22]

.richard said:

How can you give a garage a fault which isn’t there for weeks?

Unfortunately, with great difficulty. If a fault occurred that the control unit could detect, there would be a fault code stored that would show up on their diagnostic scan as a previous fault, even if it wasn't occurring at the time. If they haven't been able to find anything, it sounds like it certainly didn't create a fault code. Do you know how far an extent they went to try to find it? In the instance of no fault codes present, there are avenues to go down, but it depends on how much money you want to spend on finding the problem. You'd be looking at them going back to basics with wiring checks, plug checks, checking for water ingress etc; all of which could still turn up nothing untoward. There may be potential then for internal component faults causing it, but you could then be paying to replace parts as a process of elimination.

May be something worth getting a reputable auto electrician to look at if you really want the issue sorted, as they may have a better labour rate to take the edge off the cost a little bit. With electrics being their bread & butter, they may also have dealt with similar issues before, and more frequently.