Wife drove the car today when the alternator not charging message displayed on the dashboard and the steering got heavy. Crank shaft pulley rubber dampener had sheared off  throwing the auxiliary belt off. Quite easy to replace it’s held on with 8 multi spine bolts but needs a pry bar and a gentle work on both sides to get the old one off. You need a slightly bigger multi spline socket for the auxiliary belt tensioner to pull it back to get the bolt on and can all be done from above. Quite a common thing to happen so hope this helps somebody in the future. Quite pricey if you try getting one off the internet as euro car parts list it at £339 but if you ring them for a price with a trade account it’s £96.

Wowsers that's a big saving. Thanks for the write up Dave I'll pin your post so it'll be easier for other q7 owners to find 

I’ve got a 2014 Q7 and same happened to me last year in the Lake District, at 10pm on a Sunday night.  Problem is, the pulley shouldn’t be rusting away like that, it a low quality part that Audi could easily have put right.

 

My pulley was £350, from a local car parts place, VW were asking £550 at the time (parts - not fitted).

 

If people can get them for £96 from ECP I’d recommend doing it as preventive maintenance as you can’t really drive without it.

 

Shame really - I’d expect parts like that to fail on a Citroen C1 but not a Q7!