I have been better able to cope with the foibles of my oft off-song old WRX because I've always had the backup of my trusty old 525 (fitted with a Sigma M total closure alarm/immobiliser system) - until last night! Visited a pub a few miles away, arranged for Mrs to come and collect me and car, pressed remote - nothing.
Unlocked car with key, no alarm sounded but dash mounted LED wasn't lit or flashing. My conclusion, ha ha, remote batteries f****d. Left car there and returned this morning with new batteries fitted to remote - nothing.

The alarm system seems totally dead and the immobiliser appears to be locked in somehow. Eventually I got the AA to tow it home.

It has a multifunction keypad inside the car but I,m not sure of the PIN number to reset it - I phoned the previous owner who had the system fitted and he thinks it's the last 4 numbers of the VIN but isn't sure.

I know this isn't a Subaru issue, but does anyone know of a relatively simple (DIY) route to cut out the whole system - the car's not worth nicking anyway.

Cheers, Rod

Er, not as simple as it sounds to "cut it out". You will have to trace the wiring from the alarm unit back to where it has been linked into the car main wiring. It does act as an immobilises [as youknow] so there could be up to 4 [four] circuits which have been looped into. So simply cutting all the wires will not solve the problem, you are best geetting an alarm specialist to call and sort it properly, otherwise it can cost you more than you expect if you only call them in as a "last resort".
Noy only that, but most insurance companies dictate that it is mandatory to fit this type of alarm system, by removing it and not re placing can invalidate your insurance.
It also adds to re sale value if fitted and working.

Thanks for advice and caution Scoobyslut. But.....IT'S DONE!.....and only took about 10 minutes. I haven't got an alarm or immobiliser and I do have to turn the key to lock/unlock and I do have to press a switch to shut the sunroof and windows...but I can use it! As I said, it's not worth nicking, really - 11 years old and 230k, or worth £250+ for another system, but at least I'm mobile in comfort again. I will try and get the alarm ECU checked and replace if not too dear.

Although the system had been fitted quite neatly, the lazy sods had spliced into the vehicle loom right by the ecu (rather than following it to hidden areas - friend who's a mechanic by-passed it. Scary, really.
Rod, Lesssadgrandad.