b'nent of the high pressure pump. The DME activates the volume control valve. A rail pressure sensor is fitted on the stainless steel rail. In the rail, the pressurized fuel is stored temporarily anddistributedtothehighpressureinjectors.A silicon element on a metal membrane measures the fueldelierypressureintherail.Themeasuring range of the rail pressure sensor is from 0 to 160 bar. The rail pressure sensor delivers a proportional voltageovertheentiremeasuringrange.Therail pressure sensor is supplied with a voltage of 5 volts and grounded by the DME. The signal for evaluation fluctuates depending on the pressure. The measur-ing range of approximately 0.5 to 4.6 volts corre-sponds to a rail pressure of between zero bar and 250bar.Thereisanemergencyactivationofthe volume control valve by the DME in the event of a complete failure of the pressure sensor. The signal from the rail pressure sensor is an important inputtheearlymodelsfail,althoughnotalwaysallat signaloftheDMEforactivationofthevolumeonce. Some complaints are multiple misfire codes, control valve. and one of the most common complaints is with a cold engine. The engine stumbles when cold and has The Problem poor response off idle. Sometimes the engine is also Sowhatstheproblem?Well,manydifficult to start. It can quit altogether as well. This alreadyknowtheanswer:was not a small issue. The failure of the HPFP affect-The pumps onedthousandsofBMWvehicles,from2007thru 2010. BMW went through four redesigns of this fuel pump before coming up with what appears to be a solidsolution,withfailuresstilloccurringupto 2015models.EarlymodelsR56withN14engine packagemayhavecodesof:P1216,P3007,and P3091.Monitoring the Fuel ControlThe processor determines faults in this system by conducting a rationality check. The diagnosis of the 32'