Having problems with my wrx 05 the central locking and the immobiliser stopped working on my key fob batteries fine and it’s sending signals out been tested , iv taken the battery off and charged it , the alarm keeps going off opening with the key and it even bumps off but alarm keeps going off !
Can’t open it with central locking and turn off the alarm and immobiliser!
Iv had a car lock smith out to reprogram the key in and couldn’t because of the alarm it’s pissing me off could anyone help me with this please Been over 6 weeks now can’t drive it

 

The key has a transponder chip inside it which communicates with the ECU via an immobiliser module. If it doesn't recognise the key when it's inserted into the ignition the ECU activates its immobiliser circuitry. If it does, the red key symbol on the dash goes out and all is good.
With the Sigma alarm fitted the single button key's internal pcb activates/deactivates the alarm which in turn operates the central locking. The alarm also has an immobiliser circuit or two.
It sounds as if the key is no longer paired/linked to the alarm, so the only way to deactivate it is by entering it's PIN into it via its keypad.

Do you know the PIN for the alarm (4 digit number)?? Do you know where the keypad for the alarm is??
Have attached a copy of the Alarm owner/operators manual.
You should have 2 keys but usually the 2nd one goes missing when the vehicle changes ownership.
If you don't know the PIN, and no working key, then you will need a Scorpion/Toad/Sigma technician to reprogram the unit.

There are many threads regarding Sigma problems in the Security forum
https://www.scoobynet.com/security-16/

 

I had my Sigma taken out of my classic turbo last year, as it was clearly dying and past it. I had a dealer repair done 2 years before, so decided it was time to change. £450 later, fitted on the drive by someone who clearly knew all about Sigma. Just have to bite the credit card bullet. Not a sigma now !