BMW LogoBMW’s Incorrect Fuelling Protection System (IFPS) system is now standard on all diesel-powered BMW cars, previously available only on the 1, 3, X3 and 5 series. Now the 6, 7 and X5 models also have the system.

The IPFS works by using two opposing contact patches located in the fuel tank neck. A diesel nozzle is thicker than a petrol nozzle, so only a diesel nozzle will be able to touch these two contact patches – this will release the locking system.