Help. The 159 has broken down twice, now and both times the fault code is the same. P0091 and P0094 Fuel Pressure (high pressure pump input regulator).
First, what is the pump input regulator and secondly, is this a sensor fault or a regulator fault??
Are there any other causes of the same code?? Fuel filter, scavenger pump, leaky injector, etc??
Any help gratefully received.......
Once the ignition has ben turned off she starts and runs fine. The only other issue I remember is the occasional 'misfire/hesitation' feeling as you come off the gas and then go back on it.
2009 159 1.9 JTDm 16V with 65,000km on the clock.