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What is U3FFF Fuel High Pressure Circuit. Fuel Pressure Lower than The Reference Value?

17K views 6 replies 5 participants last post by  petej247  
#1 ·
Dear Community,

Recently I wrote some information request about certain fault codes that my 2016 blue hdi 1.6 diesel produce.

After taking my car to the repair store to read the code 2 weeks ago, they cleared it, but the following code appeared again for the second read:

U3FFF Fuel High Pressure Circuit. Fuel Pressure Lower than The Reference Value - temporary.

Could you please advise me what service should I ask from the repair store and how serious this issue is?

Thank you!
Ben
 
#4 ·
I have same issue mileage its 123k and fuel filter was changed about 15k back.usualy show that message after few longer start stops. Fuel rail pressure difference 10-15bar lower than reference under load and 5-10bar idle. Sone when engine stop on lights ref value stay on 350bar but actual pressure plumes to 4bars are its that normal?
 
#5 ·
If the fuel filter has been changed it's likely to be the fuel pressure regulator on the HP pump of a failing injector. do you have any other symptoms such a loud diesel knock or poor cold starting
 
#7 ·
Hi I have the fault same code, and have changed the filter around 5/6 weeks ago as I thought that the filter may be casing the fault. The symptoms do include rough running when the Regen is requested and enabled. Fuel pressure seems to largely track the requested value.

I have
Had the PATS fluid added
Pats fluid pump replaced
Fuel filter changed
DPF cleaned and regen has happened

The issue now seems to be Regen Enabled ( notified from reader), rough running, and an almost immediate Service light / Engine light / Risk of DPF clogged / U3FFF (FF) fault

Latest screen grabs below - thanks in advance for any advice.

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