Here is a little teaser for you electronics folk. Unlocking the doors on my A4 has recently failed to unlock the rear offside door. Actuator you may suggest. Well here’s the thing. If l disable the internal movement sensor. ie double click the key when locking  the car.All works as normal, all doors unlock. Both keys behave the same and batteries good . Because of this a repair is not urgent but any thoughts would be welcome

 

My previous A4 did that passenger side front.

I lived with it but since moving it on my friend has solved it by replacing the door lock module.

I found this very interesting- my offside rear door has got exactly the same problem. The main dealer who sold me the car agreed to fix it under warranty- but would not give me a courtesy car because i'm 76. I raised a complaint- heard exactly nothing- natch.

I'll try the double click routine, if it doesn't work, my excellent local guy- Auditechnik near me in Kent will have to sort it at the next service.

You raise an interesting point about courtesy cars Michael. I think the rule of thumb is that most car hire companies will not hire vehicles to people over 75 since their insurance cover will not provide cover at reasonable rates. It seems dealers follow the same principle then. 
With the increase in motor insurance being conducted via. comparison websites, and the option of choosing whether to pay extra for a courtesy car, it becomes all important for this age group to ensure they opt for this service, otherwise they could end up without transport. 
Kind regards,

Gareth.