A3 2006 starting issue in cold weather
 

Usually my Audi is parked in my garage where temperature is around 10C, no issue starting. But it happen three times that it stay outside at temperature -5c to -15c, the engine will not start and cannot open the door with remote keys.

Had to boost the car, no starting issue in warm temperature. Its seems a voltage relay is nt engaging in cold temperature.

Any one has an idea to solve the problem

Thanks

I had the same issue and it got worse over time. I quick look in the engine bay revealed I was still using the original battery (2007 model) - once replaced the kitten purred again in cold weather ;)