bmw were thinking costs and later down the road repairs so get save money on producing it and then make money when it fails, so by hiding something away that takes a hour or more to remove replace etc might make them money done the road, and also if use a small poor made pump as well knowing that the high pressure pump needs the fuel pressure to cool and lubricate the metal blades within it is a bonus ball,, all eu makers are doing this it would seem as well as making as much encoded as they can then make the diagnostics as hard as poss and have codes that only they have and wont give out etc,, EOBD was meant to be a diagnostics that all maker used same parameters on,, its turning out they are going in a new direction to prevent repairs by using )-codes and most now use a internet server for diagnostics that only dealerships can register to.. and the new hybrid gear will only get worse i fear,