Mine lost communication with the M99-T2 so had to be replaced. Not keen on the £10 system by-pass plug so I purchased a new immobiliser from Abacus Car Alarms for £232.50 all-inclusive.
It’s a direct replacement, only needs one of the two plugs fitted to the original, it has a new green led indicator light (with plenty of wire and a sticky pad to locate it on the dash by the ignition switch for ease of viewing) and two new round RFID tags for arming/dis-arming the system.
As it’s RFID it works on proximity, when 10 meters away the immobiliser self-arms after 35 seconds and deactivates after 5 seconds once within 10 meters.
If your paranoid like me there is an RFID pouch included to put the tag into which contains the signal and once inside starts the arming process.
For me the system works perfectly. If I take the key out of the bag on the way to the car, the system has been dis-armed by the time I’ve got into the driver’s seat, if I put the tag into the bag when I switch the ignition off, the system if armed by the time I am walking away.
The tag battery (CR2032) lasts about two years.
The standard ignition key button still activates/de-activates the intruder alarm system (M23-T2) and red led still works as normal.
PS. My only connection with Abacus Car Alarms is the purchase of this part. I mention them as they gave good service, they answered my questions quickly, succinctly, truthfully and the part was delivered the next day.