I have been having this problem for about 2 weeks now. 2004 XJ8 the trunk comes unlatched at random times. It has occured with the car parked and locked, it sets of the car horn alarm. It has occured while the car is in motion. It has even occured right after I close the trunk lid. The lid closes and the latch pulls the lid down tight. Start to walk away and the lid unlatches. Can tell when I use the remote to lock the car the horn beeps. I go back and the lid is no longer latched. Is this a simple clean some contacts fix? New to Jaguars and don't know where to start troubleshooting.
Thanks for any help.

 

I don't know the answer but would like to post some ideas for you.

Scan for codes.

For the time being try locking the boot manually with the key and see if that stops the problem.

Are the contacts on the button making randomly without being pressed?

According to the electrical guide there are microswitches associated with the boot latching motor.

I have had microswitches fail in door locks.

 

I's possible the NO switch for the boot release id faulty and or you have a wiring fault to the REM.
IE you are getting a short that triggers the boot release signal on the REM

It is not likely that the wiring the REM or the boot solenoid is at fault as this is triggered high to operate the release but there is a slim chance of a short to 12v here as well

I would remove the wire from the REM and see what happens
If the fault goes away you know its the switch or wiring to the REM

You can access the boot with the key while you have the wiring disconnected
To test for a short, reconnect the wire on the REM and disconnect from the switch
If the fault comes back you have a short. I would just bypass the wire and run a new one
Otherwise you need a new switch

If you sill have the fault you have a faulty REM. Try a re flash before replacing. Also look at the battery status. Weird REM stuff is an early sign of battery on its way out. After that you will get keyfob issues then the Christmas tree on the instrument cluster

cheers
34by151

 

Thanks for the information. I will have to look at it closer. It has behaved the last couple of days.

 

I am having the exact same problem with my 2006 XJ8. It is very frustrating. Sometimes it can go a day or so without happening and then some days (like yesterday) it seems to happen every couple of minutes. What did you find?

 

I found that if I used the keyfob to open the windows and sunroof remotely, I would have this problem for several days. I stopped opening the windows with the remote and have not had the problem since. So I did not actually find a cause or a fix. But it seems to have gone away for now.

 

Thanks. It is weird. I have never used the remote to open the sunroof or windows.