Hello,
I had quite several remote failures lately. Intermittent failures so that I have been thinking to replace remote batteries
The LED green and red lights work on the remote but the doors are not locked and unlocked anymore.
I replaced the two CR 2016 batteries with same voltage single CR 2025.
LED lights work on remote but I can't unlock my doors.
I start suspecting it is something different.
Could the internal receiver on the car be bad ?

 

Why one battery? Remote needs two for a total of 6V to operate correctly. LEDs will be fine with one 3V battery but remote won't work with a single one.

 

Don't use the cheap dollar store batteries ( low current but show voltage ) , and there is a TSB on the remote as there was a change over the X300 production . Note on the battery cover the frequency in hand .See bellow :

JagRepair.com - Jaguar Repair Information Resource

See TBS 18 - 4 to 18 - 12