What is this electrical part?

[ColdCase]

We have a 2008 A4 Quattro. I was under the car this AM and heard something rattle as I was tapping on the belly pan/splash shield. I notice this electrical thing hanging off the wire harness near the passenger motor mount area. Does anyone know what it is and where its suppose to be attached? Kinda hard to see up into that cramped area.

Thanks

[Theiceman]

looks a bit like an anti knock sensor. Not certain though.

[Okedokey]

Scan the car, itll tell you.

[ColdCase]

Thanks, I was hoping someone here would save me some time.

There are no error codes, as far as I can tell.

The knock sensor looks a bit different, has a hole through the middle and typically black.

I binged A4 sensor and none of the images that popped up look like this. I'm going to have to take a closer look tomorrow. Perhaps I'll try disconnecting it and see what error code pops up.

[aluthman]

Looks like the clip off a tiptronic motor mount. Definitely not a knock sensor.

[mtroxel]

Looks like the clip off a tiptronic motor mount. Definitely not a knock sensor.

That was my thought, but that's just on the driver's side isn't it? Or did they add it to the pass side in later B7 years?

[ColdCase]

Yes, thanks guys, that seems to be it. I'm far from an Audi expert and I would have never figured this out without your help. The sensor is hanging down on the passenger side but the harness is long enough that it should reach over the the drivers side where the engine mount sensor seems to be missing. It is an automatic.

My understanding, from googling the engine mount sensor, is that it doesn't hurt anything to leave it disconnected. There could be a bit more engine vibration felt under some circumstances. Its not setting a check engine code, and this Audi has 120,000 miles on it anyway. Not quite as smooth as new.

I just want to wait for a warmer day to pull of the splash shield and see if I can connect things back up and put some duct tape on it .