britorean

In case it's helpful to anyone, when I ordered the part last week from Cardiff Audi (who deliver natinoally), they said they have them on their shelves. It was the latest version with B at the end of the part number.

An update from me too. I ordered the sensor (5Q0 906 207 B) from Cardiff Audi on Friday and it arrived this morning. It took a few minutes to remove the old sensor (I think I was being too careful not to break anything off) - the hardest part for me was to unhook the latch on the sides, but installing the new one was super easy. Both brake servo and stop/start warnings disappeared immediately after the sensor was replaced. All thanks to everyone on this thread and especially Ambrose whose posts I found extremely informative! Obviously I'm not impressed that these parts are failing in the first place (or that they could lead to bigger safety problems), but I am hugely impressed by everyone on this forum coming together to help others. I would have been without a car and few thousand pounds poorer otherwise!

This is so helpful and amazing, thank you so much Ambrose! What a legend.

I had the "Brake Servo Restricted" message come up on my '16 A4 on Wednesday, and having come across this amazing thread in time, I have ordered the replacement brake servo sensor. Hopefully it gets here soon! I don't really know my way around the car's bonnet, though, and if anyone is able to do a short video showing how to unclasp the existing sensor (I don't want to break anything off!!) then it would be so much appreciated.