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