just to clarify -- the two areas of programming are separate..... REMOTE CONTROL OF DOORS you only need one remote key to be programmed/program to open the doors remotely (GEM system) - up to a maximum of 4 per car.... this relies on the active transmitter in the key fob STARTING THE CAR AND KEEEPING ENGINE RUNNING you need two working keys to program a third and subsequent keys to start and run the engine (PAT system) this relies on the passive chip in the key