159 Alarm randomly going off after battery reset
I have recently bought an 08 reg 159 and initially had a problem with the central locking not responding to the key fob; I was having to lock the car with the key. This de-synchronisation had probably been caused by a flat battery the car suffered whilst standing over Christmas before I bought it.
I was about to get the key re-synchronised at a specialist but tried a tip I'd read about whereby sometimes key fobs will marry up with the car again if the battery is cut off for 15 or 20 minutes. This worked, to my surprise, and |I was happy not to have to pay money for codes etc.
However, I am now back to square one and having to lock the car with the key (therefore the alarm isn't set) as the alarm keeps going off randomly whenever I've locked the car with the fob, sometimes several hours after being locked. I have been pressing the button next to the interior lights switch to de-activate the volumetric sensors when I get out and I have checked the battery charge, and so I presume both of these can be ruled out as causes.
Can anybody shed any light on what the problem or solution could be? Thanks