Thread: Fuel pressure errors

Hey mate,

Fuel pressure changes constantly with engine load and throttle etc. The ecm changes the trail pressure to suit what it needs.. When the rail doesn't match the ecm requirement, you get as fault code, most low pressure cases are the valve on the common rail, or high pressure fuel pump failing. The valve regulates the pressure to the rail, there is tons of step by step on how to test everything on here, just search HPFP or the code.

With my errors, I'm just going to replace the HPFP. My Grenadier isn't due to arrive just yet.

I see a few cheaper remanufactured VDO pumps - are they OK?

Cheers
Luacs
2011 D4 2.7

Here's my log of values just as the restricted performance comes on:

Screenshot_20230624_130503_IIDControl.jpg

I assume it is the HPFP? Are the pressure values dropping because it is going into limp mode? Or is the HPFP causing the pressure to drop? Any help would be appreciated..

You can see the PCV opening up to 52% and the fuel pressure not following. The PCV is sticking.
If you were watching that live and got off the loud pedal as soon as you saw the PCV spike, then stab the throttle hard you'd probably be able to "drive around" the fault (so basically close it then open it hard).

I found it was gentle application of power that manifested the fault. The valve has to be maxed out for about 2 seconds before the fault is registered, so if you can get it unstuck before then you can prevent the fault logging.