2000 Subaru Outback. Keys lost, does the key need to be programmed to disengage the immobiliser? Or can the door lock be removed to get new key cut and start the car as well with just a plain key

Dealer needs to program it to the keys that you have.

2000 did not have transponder, that was in 2007. Just hey a key made

best advice is to get a locksmith to do the job. They will be able to put in a new tumbler, supply the correct fob keys for the immobiliser and possible program it to the vehicle . IF not you will have to take the keys and the vehicle to a service dealer to have it programmed.

Subaru Keyless Entry Security Alarm Immobilizer Key Remote Start Systems...

go to the dealer

Obtain all keys/remote controls. Remove driver's side kick panel/lower 'A' pillar trim. Connect central locking registration connectors (white) - black wire and black/blue wire Fig. 2 . Unlock the vehicle using the key. Program first key/remote control as follows: Press unlock button Fig. 1 [1], then lock button [2]. The door lock should lock and unlock in sequence confirming programming of first key/remote control. Repeat programming procedure for remaining key(s)/remote control(s). Once the last key/remote control is programmed disconnect central locking registration connectors. Check operation of all programmed keys/remote controls.

You should contact a good lock smith,most of thease guys can re programme a new key all you need is to remove the door lock and a new key can be cut from this.Also they will be half the price or more than a dealer.

you can just try taking off the steering cowl and unscrewing the black cap (multifuntion switch/ignition switch) what about the steering lock?
If you have lost the keys forever then you may as well drill out the lock? youll have to buy a new ignition barell anyway.....
It's likely the car is immobilised though, it needs the proper key! although sometimes the immobiliser is disabled, sometimes it works sometimes it dosent...
good luck!
Leave feedback please.

I think your model vehicle is subject to 2 recalls. The first is to have the ECM reprogrammed and the second is for a cruise control clip. Both of these recalls exist for sure and may be a good place to start. You can check on "MySubaru.com (you will have to register) to see if your vehicle is affected. If the ignition was replaced having the ECM reprogrammed and the keys programmed might fix the issue. May fix the cruise control as well.

After ages searching finally found this on the Cobra site.... A8510 KEY PROGRAMING Ensure the immobiliser is disarmed :- 1) Switch the ignition ON and OFF three times then back to the ON position within seven seconds. 2) The LED on the dashboard will light up signaling the unit is in programming mode. 3) Touch an already programmed key onto receptical, the LED will extinguish for one second 4) Repeat step 3 for all other keys (Max of 4 touch keys) 5) To exit programming switch off the ignition key (unit will automatically exit programming after four keys) NOTE :- 1) Programing procedure can only entered with the system disarmed. 2) If all keys have been lost the system will need to be replaced