I am coming across two different issues with my 2012 Audi Q5 and I am wondering if they are related. Note that the car started out as being bought in Southern California, lived most of its life in the Mojave desert in warm climates and is now in the midwest in a city that get its fair share of winter blasts


If I have the car completely outdoors in a cold climate, like 40 degrees Farenheit or below for anything more than 1 hour, my key remote fails to open the doors of the car. I can sit there and click the remote all I want and the car will not respond in any way. It's as if the radio that picks up the key fob is not even on or frozen in some way. I have to open the car using the manual key and it works just fine.


If I have the car in a covered garage (not a private garage, more like a parking structure), it is still cold but not as cold as outside. It gets to be like 50 degrees Farenheit or below. If I leave the car for more than about 16 hours or so, there is a pretty good chance that I will come out to a dead battery. The car will simply not start and requires a jump start to do anything. When it's very cold out, I have had the battery die on me in less than 12 hours of the car sitting.

Obviously, Issue 2 could be caused by a phantom power drain. But isn't it also possible that it's caused by Issue 1? Is there something in the operation of the key fob radio that could be causing the issue here? Or even both issues?

  • Have you replaced the battery in the fob? Have you replaced the vehicle battery? Have you checked for a power drain? Have you considered disconnecting the battery overnight to see if the issue still happens?
    – Solar Mike
    Feb 18, 2019 at 8:36

2 Answers 2


Issue 2 sounds to me like your battery is failing - they only last 5-6 years normally, so if it's the original, it's likely to be EOL - cold weather commonly causes a tired battery to fail as they can't store as munch energy when it's cold.

I suspect this may also be the cause of issue 1 as well - it may be that if the battery is low it may shut down the radio in order to conserve power?

I'd check the battery, and if it's still the original, replace it.

(I've also clarified the units in your post, as for most of the world, 50 degrees (C) is seriously hot!)


As @NickC says your battery is likely not up to it. My personal experience with northern midwest winters was that not all batteries are created equal, and that even the best of them only last 3-4 years at most in that kind of cold.

Batteries are not the only thing that suffer in cold though, I've had trouble with door locks and locking mechanisms as well. I found that at -30 or so some of the greases used in my cars' door mechanisms lost their viscosity, making it harder for the electric openers to do their job, sometimes using the key was the only way to overcome the resistance. I've heard of relays failing in that temperature as well, although it's never happened to me personally.

So the first port of call is the battery, it may not have enough power to overcome the increased resistance of cold lubricants.

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