XJR Alarm going off

[Tramami]

Now in my 3rd week of my first Jaguar car, a 2005 model XJR in Jaguar racing green with ivory leather, love the car, but last night the alarm went off on my drive, the car was parked all day and alarmed which included deadlocking, could see no reason why it went off, as this was after 11 pm i found out how to turn the tilt and inside sensors off, the alarm did not go off again, from this morning the car has again been fully armed with no faults, question has any body had this or any idea what could be causing the alarm. Thank you in advance Alan

[barrywi]

Is the battery on the car OK? Sometimes that can trigger the alarm. Also spray all earth points with WD 40 and oil/spray white grease as they can cause problems too. Don't forget the ones in the boot under the floor and the battery earth strap, and tighten up the battery connections if loose. May not cure the fault but it will eleiminate several potential causes.

[J44EAG]

I occasionally get this on my S-type if I leave window or sunroof slightly open. The car has a pressure sensor that reacts under normal circumstances if air pressure changes drastically ie if a window is broken during an attempted theft. A similar effect is produced during a gust of wind if a window is not completely closed.

During one violent storm, I had also to close all the dash air vents to prevent the alarm going off.

Just a basic idea which might be relevant.

Mike

[robv12]

can't comment on a 350, as our 3.0 350 was the paragon of virtue and vice free in our 3.5 years with it, and the XJR is too new to comment

BUT, on a 308 the body processor can give odd conditions, it gets damp, begins to corrode, affects all cars not just the older ones, I had a 3 year old 2002 car with that exact fault

[Tramami]

Thank you for the replys, it has not gone off again, will change the battery as its been on the car since new, every thing else is fine so far, just after it happened i left the car for the weekend with the sensors off, at least thats what i tried to do, the owners book was not that clear on this. Alan

[PaulGover]

I occasionally get this on my S-type if I leave window or sunroof slightly open.
...

Seconded - I got called by the security guard at work 'cos my X308's alarm had gone off. I'd left the windows about 1/2" down to allow the hot air from sitting all day in the sun to escape. The crosswind triggered the alarm, so I have to bake if I don't want a call from security. Now I understand why you can open all the windows at once using the key in the driver's door!