The locking system in my 2009 A4 Prestige has stopped working. You can still use the smart key to lock/unlock the doors but the touch- locking system and proximity unlocking system has stopped working. Nothing in manual about this feature. Anybody have an idea?

 

The same thing is happening to our '12 A4, intermittently.
Did you ever get a resolution?

 

This is usually down to one of the door handle sensors being faulty. If one sensor fails, it pulls the whole system down. You would need to have the fault memories checked with a scanner to identify which handle has been detected. Then it's just a matter of removing the handle and replacing the inner part of it.

 

Thank you, I'll promote this to my dealer early in the week.