XF Key Fob Failure (2011)

[John D9395]

Key Fob over the last few weeks has been getting worse in that you almost had to be touching the car to unlock it, the last couple of days, once open, key wasn't recognised, had to put it into the docking port.

At work today the car locked, but then wouldn't unlock, so I had to revert to the emergency key to get in.

I then changed the battery, still can't remote open the car, Docking Port still recognises key.

Once home I measured new battery voltage, 3.12 vdc which as it was greater than 3 I though was OK, however, I had another spare battery available, measured at 3.31vdc, put that in and still no change.

Spare key works fine.

I seemed to remember on my S Type that there was a synchronising routeen that you had to go through?

Any guidance / help appreciated.