Central locking system

[FordFocus1]

Hello everybody. I have an unusual problem that once I started thicking about I could not have solved it. That it is why I am writting here seeking advices. So my friends car central locking system does not work. The car does not have key locks so you can not close or open the car manualy. I am wondering where the problem might just be. Is just the key battery flat and in need of replacement. When replaced would the the central locking system work? Or is the key in it self just broken and in need of replacement or at least the guts of the electronics of the key? Or is the problem deeper in the very inside of the car of the central locking system? I really do not know that is why I am seeking advice on the mentioned topic. I would appreciate every advice.

[WES180]

What is your friends car?

I would replace the key fob battery first and see what happens.

Has your friend got a second key fob to try?

[FordFocus1]

I do not think there is another key fob to try for that. The car is not a Ford actually but I sort of thought that the problem is or could be universal for every car. I guess I will check for the battery and hope that it is that simple.