I've got a 2016 L405 with the 3.0 TD6 engine. It currently has a difficult time starting (Cranks maybe 3-5 seconds before firing up) and once started it will idle for a few seconds then stall. When the engine is cold it may only stall once, but when the engine is warm it may repeat this 5-6 times before it stops stalling. Once running it idles and revs smoothly with only occasional hiccups. Following this it will typically run fine but when driving and coming to a stop once the engine reaches idle it may stall again. It has also gone into restricted performance once or twice. I cleared the engine codes then drove the vehicle on a short drive around the neighborhood and the following codes for the fuel system returned:

P00C6 - fuel rail pressure too low - engine cranking
P0087 - Fuel rail/system pressure - too low
P0088 - Fuel rail/system pressure - too high
P228F - Fuel Pressure regulator 1 - Exceeded learning limits - too high

Any ideas where to start?

When monitoring actual fuel pressure vs desired, I'm seeing a lot of variation on bank A along with the sensor reading fluctuating between 220 and 660 kpa with the engine completely off. It also looks like the fuel pressure never quite reaches the desired pressure.

I know there was a TSB for the 4.4 TDV8 where I believe the rail pressure sensor wiring ground was faulty? Could that also apply to the 3.0?

I've seen crank position sensors that act up cause similar symptoms but without the accompanying low and high fuel pressure codes.

Any suggestions are appreciated.

 

It could be caused by the sensors for sure but I would also check the fuel injectors.