I have a 2001 XK8 Convertible with 50K miles on the odo. Three weeks ago, the doors spontaneously unlocked themselves while I was driving. I manually locked the doors, but they almost immediately both unlocked. I repeated manually locking the doors, and after seven or eight cycles, the doors stayed locked. This unlocking problem randomly occurred a few more times during the following two weeks. The battery in the car was six years old and barely tested out at 12 volts, so I assumed the problem was just one of those electrical gremlins caused by a weak battery with low voltage. (When starting the car, the doors would automatically lock themselves when I shift the car into gear, as normal.)

I purchased one of those giant Interstate MT-P 93 batteries and slowly charged it up to 13 volts before installing it. I did a hard reset with the old battery removed, and I checked to see that the cables were clean and tightly fixed to the new battery posts. I reset the automatic window drop and everything seemed fine for a few days. Unhappily, today the spontaneous unlocking problem returned. It happens only while I'm driving, and with repeated manual locking, the doors will stay locked, at least or a while. The remote key fob works the locks with no problem.

A possibly related phenomenon: Before the battery was replaced, the car alarm twice went off spontaneously. Unlocking the car with the key would stop the alarm. So far, that problem has not returned.

I've searched the XK8 / XKR Forum, but found no similar automatic door lock problem.

Anybody know what the fault is? Any suggestions? Thanks in advance.

 

I have a very similar problem....doors lock and unlock several times all by themselves....alarm goes off randomly....all while parked. Have 2 month old battery.

Anyone?

 

Both cars likely have a failed/intermittent microswitch in one of the door latches probably. If the car is interrogated with the Jaguar diagnostic equipment, the 'Last Alarm Data' can be read. That will give the offending entry point to suggest which microswitch has failed.

Good luck!

 

As these micro switches fail Jaguar issued a fix and made available new switches to fit to the lock mechanism.

Find it here JagRepair.com - Jaguar Repair Information Resource

 

Steve and Jim: Thank you very much for the clues and lead on what to do about the door locks. I'll have my dealer run the diagnostic test the next time I'm in for service and will post the outcome. The problem does seem to have abated a bit since my original post, however. Again, thank you both.