Hey all I have an 2,7d 08 XF

The last couple of days I've gotten an error message: "gearbox fault" ( or "transmission fault"). This has only happened when I try to start the car after sitting in the cold for a few days and it wont start with first attempt, it tries and fails, but on the second attempt I get it going and this message appears. I let the engine run for a few minutes then turn it off and back on and it starts perfectly fine with no error messages.
I haven't given the car a good run for a while before that, but did it today and everything seemed to be fine with the way the car ran. So is it likely the battery is bad and thus gives a wrong error message, or should I be worried about my transmission being faulty? I've seen the red battery icon flash for a second when starting the car, but never has it failed to start before, although it's been colder now and I havent used it much at all. What you guys think, need to go change the battery or would just giving it a good run often do the trick?

 

Sounds like so many battery issues. You can read threads about it and the voltage it should be and how & when to measure it. (12.6V after standing overnight and engine still off.)