I'm new to Jaguars and last week my key fob suddenly stopped working. Couldn't hey in the car because I only habe one key. I tried the key hole on driver door which also didnt work. I got in through the trunk and folded the rear seat down.

-I replaced the battery a couple of days later still nothing. (During battery replacement the battery was out of the key for about an hour)
-I also tried the open door, high beam flash, etc procedure and still nothing.
-So I took it back apart to clean it a little better because it had sticky green residue on the metal and board. Tried it again and still nothing.

In a thread here somewhere a member suggested to rapidly press unlock 5 times then lock once. It worked! Sounded silly when i first read it and felt silly doing it but it worked for me (04 S-type 3.0 V6) the doors didnt lock right away but i did hear a module or something like clicking. Then i pressed the unlock and lock to test if its working properly. If you guys haven't tried this I highly recommend trying it. If this didnt work i was going to get an aftermarket system.

In the last week, crawling through the trunk was the only way to get in without a working key fob. Hopes this help someone who's in the same situation with their key fob.

 

It doesn't have to be 5 presses. It's just so the car can resync with the fob.