Audi S3 - alternator pulley slip & Serpentine belt mangle

[ensnare]

Unfortunately just had a situation with the S3, was reversing into our garage after the usual commute and heard a horrible squeeling noise, I immediately turned off the engine to take a look and was greeted with this sight:



Managed to remove most of the serpentine/aux belt (think this is what it is?), to reveal this:



Looks to me like the alternator pulley and slipped off into the wind screen wiper reservoir, causing the belt to slip off and get mangled. Unfortunately it looks like it's taken a wire with it too, you can see the end of a bare piece of wire in the top left of the second photo, there's also a piece of plastic with a hole in it, is something supposed to be attached here too?

When I turned off the engine, the DIS showed a low oil pressure warning at the same time, wondering if this wire is perhaps an oil pressure sensor? I've checked the oil levels and everything seems normal.

I'm wondering if i'm OK to start the car again, or if it's advisable to leave it off? Any idea what the wire could be? and how this could have all happened?

Edited by ensnare on Thursday 27th June 10:51

[ensnare]

Seems it's an Aux belt, but also sometimes called a serpentine…

Anyway, new alternator has been installed and some rewiring of wires taken out by the belt and it's back to working like new. Seems you can't buy just the pulley part of the alternator, so needed a full new one!