Lost or misplaced your BMW keys? BMW vehicles use several different key and immobiliser systems, each with its own replacement process. Older models from the mid-1990s up to some 2011 X3 E83 vehicles run on the EWS system, which uses a traditional bladed key inserted into the ignition. From 2005, many BMWs moved to the CAS system, where a slot key is pushed into the dash and paired with a Start/Stop button, sometimes enhanced with Comfort Access for keyless entry. From 2011 onward, newer models introduced the FEM smart key system, allowing you to start the car with the key in your pocket. These FEM systems are highly secure, and in an all-keys-lost situation, replacement may only be possible through a BMW dealership — which is why having a spare BMW key is always a smart investment.