My 2010 XJ L 5.0 s/c LHD spends most of her time parked up as I work abroad. When my wife came to start her, there was no charge in the battery. Car is normally locked to avoid power drains, as we’ve been there before.
Anyway, I removed the battery - it was down to 8.5V - charged it up again, and now reading 12.6V.
As soon as it is reconnected the alarm sounds, and will not respond to the key. Also the “Smart key not found” message appears on the dash. Key battery swapped with a new one, which works fine with our Focus. No response in the XJ, even when held close to the sensor under the dash.
No response to the start button, but the windows operate. I’ve checked all fuses in all 3 distribution boxes, none are blown.
So now I’m stumped. Any ideas on where to go next would be appreciated.

on another tack, the RH front shock strut has had the dynamic ride wiring chewed by a rodent. But I’ll worry about that some other time….. I’m only here in Spain for another week ☹️

 

Yes replace the battery and see what happens?
I think that one is done.
.
.
.

 

Yes, done that. I suspect it’s more rodent damage somewhere. Got a mechanic coming out to dig a bit deeper as I have very few tools here, and a thieving builder nicked my diagnostic tool a while back 🤬

 

I feel for you! Rat and mice damage can be anywhere and everywhere just depends on how long they had to work on it.
.
.
.