S3 alarm keeps sounding when unlocking car???

[localknoxville]

hi all, totally frustrated with the car, when I lock it using the key fob, no problem but when I unlock it the alarm sounds, it's driving me mad, it ONLY goes off when I unlock it
Any ideas as to what might cause this issue??
I have pulled out the central locking pump and it's dry, there was no sign of water damage and the foam casing surrounding felt dry too
Could it be the key fob batteries??
I have also read that parking on an angle could cause it, is that right??
I have scanned it and it didn't throw up any fault codes either, head scratcher!!!
Any help or advice would be grateful, thanks

 

[EXSpartan36]

I can't remember exactly how to do it but you can read the alarm stack with vcds lite which should tell you the last 10 alarm causes.

 

[JonnyDerv]

Mine did this, it was the boot, sprayed a **** load of electrical cleaner into the lock, not done it since.