How to Program a BMW Key Fob Many BMW cars come with a key bmw fob that can be paired with a compatible smartphone. This feature lets you unlock and start your car using your smartphone and also share keys with family members. A standard BMW fob is designed to withstand normal moisture levels. A few dings or dropping it into the rain should not cause any harm. Keys with transponder It's best to buy new BMW keyfob from the original manufacturer. These fobs are prepared by the dealer for the specific vehicle in accordance with the VIN, and services they're designed to be extremely difficult to duplicate or hack. Check to make sure the replacement key bmw fob is genuine. There are fakes on the market, and they're not worth your time or money.