2014 XF Sportbrake.

I went to lock the car yesterday and it wouldn't work. Kept pressing the eventually locked. Thought nothing of it.
Now today it does it every time after driving. Turn the car off and try to lock and it doesn't, unless I wait about 30 seconds

Done some testing and this is what I've found.

Changed battery in key fob and made no difference. Both key fobs behaving the same way.
Once you turn ignition off no buttons on key fob work. Boot release etc.
As mentioned if I wait about 30 seconds you can lock the doors.
If the doors are locked then they unlock no problem.
If I unlock and wait the auto lock will lock all the doors.

No idea if or how this would cause it but I changed the number plate LED's (already had LED's in there) then this started happening. Probably coincidence.

Thanks in advanced.

 

Maybe worth removing the numberplate lamps just to check!

 

Took me a while to figure out that, when my wiring harness to the truck failed (has twice), that I can't lock the car. It cannot detect that the trunk was closed.

 

Thanks for the replies.

I've worked out that you can unlock the car fine from the usual distance. But to lock or open the boot you have to have the fob almost touching the front windows.
Really strange fault. It's like the range has changed for the key fob buttons (both of them) except for unlocking there car.

 

I've also had problems with crappy dollar store or Ikea batteries...