The part of the key that remotely unlocks the car and the part of the key that allows the engine to start (transponder) are totally seperate and have NOTHING to do with each other.

I cut my own keys and program them. I made one key with only a transponder. Works fine to start and drive the car. The transponder talks to the EWS. The remote for the door locks talks to the General Module. Literally they have nothing to do with each other.

The Transponder requires no power and has no battery (looks like a little chip in your hand and will function sitting in your hand that way). The door unlocking part has a battery, requires power and can be operated outside of the key away from the transponder if you like.

The door unlock part is user programable using the key and the car only. The transponder requires special tools and codes (codes can be read from the EWS).

Thaniel