On a lot of newer cars the fuel injectors, fuel pump, and starter are part of the immobilizer system. The transponder in the key bow or your keyfob is checked

On a lot of newer cars the fuel injectors, fuel pump, and starter are part of the immobilizer system. The transponder in the key bow or your keyfob is checked by the car and it needs to see the right key for those parts to function. This is part of the anti-theft to stop simple hot wiring. Although I will be honest seems more like away for dealerships to charge an insane amount for new keys. If I am being generous the security would be trying to stop the car running in the event those are tampered with but I don’t entirely believe it.