Hi everyone. 2 weeks ago, I was scanning my car randomly, and saw that there was a pending code for P0089, Fuel Pressure Regulator A Performance. I cleared it and drove it for another two weeks I’ve been checking it in between, and the code wasn’t there, until today. It’s showing as a pending code, and there’s no check engine light or anything. Car drives normally. Could it possibly be because of a cold start after like a week because it cranked in the cold? Please let me know your opinions. 49,600 miles

 

When you say Pending do you mean intermittent?

 

Yes you are right. The code doesn’t show up as a stored code but rather as a pending code. Which I think means intermittent.

 

Then don't get too stressed about it. There is not a lot you can do with intermittent codes.
So long as the car runs without any permanent codes just drive and enjoy.
When the fault becomes permanent then you have something to work with and fix.

 

Thanks for your reply. I was just concerned because It came on twice. I’m wondering if anyone else got the code? I’ve only put about 200 miles on the car since the code first came.

 

Hello @Dgeedhar ,
Being that you have a 2014 W12, you have no fuel pressure regulator on the fuel rail that feeds the injectors, nor do you have a return fuel line to the tank, to explain, the 2004-10 had a one speed system for the fuel pumps, just on, with the vacuum operated fuel pressure regulator as shown in my pictures, this regulated the fuel pressure and fuel return to the tank, whereas the 2014 system has variable speed fuel pumps and a pressure sensor mounted on the fuel rail as shown, therefore lacks any return line, so, your P0089 as to being an Intermittent fault, could be a sign of the following, a fuel filter in need of change, a failing pressure sensor on the rail (part number shown), a failing fuel pump/s.

My understanding is that the pressure sensor on the rail along with the ecms sets the speed of either fuel pump to gain desired pressure, without a regulator, as in searching the 2014 fuel system, a regulator is never mentioned, nor shown as a separate part, and if a regulator was built into either fuel pump, then what would be the sense of regulating the fuel pressure before it gets to the pressure sensor on the injection rail..

You can check Scuderia for the parts diagram and list, no regulator is mentioned, and Scuderia gives the same sequence of operation of the system as is my thinking.

From Scuderia
"The fuel supply module is made up of a number of components, including the pump, a pressure sensor, and a filter. The pump is responsible for delivering fuel from the fuel tank to the engine at a high pressure. The pressure sensor monitors the fuel pressure and sends a signal to the engine control unit (ECU) if the pressure is too high or too low. The ECU then adjusts the fuel delivery accordingly.".

EDIT:
Scuderia and others list the fuel filter with the built-in regulator as be for the 2015 MY, Scuderia specifically states 05-01-2015 >>, So, that may just be a typo or misinformation, and you may have the fuel filter with the built-in regulator on your 2014, you can tell by the electrical plug connected to it.


Johnny

.

 

Thanks Johnny. Do you think that any of those jobs would be a seriously intense job to do? I mean would it be labor intensive?

 

@Dgeedhar ,
Please see my previous post, as I have added information twice, and just did a final edit.

As to the amount of labor involved, I'd give the fuel filter 1 hour, maybe a bit more if the mounting bolt/bracket is rusted.

The pressure sensor requires the removal of the intake manifold, I would give 3 hours max off and on.

The fuel pumps, let's not worry about that now.

I'd change the fuel filter first, but do tell us, has the fuel filter been changed while you have had the vehicle ?

Johnny

 

@Dgeedhar ,
Just to be clear, it is said that the intake manifold is to be removed for the replacement of the pressure sensor, BUT, if you look at my pictures, one can see that it may be possible to gain access and replace the sensor without removing the intake manifold, it looks tight, but I would try it before pulling the intake, this is of course if you need the sensor replaced at all, like I said, let's start with the filter, the easiest to get at.

Johnny

.

 

Thanks Johnny. The Fuel filter hasn't been replaced since I had the car, and I don't think the previous owner did either. I plan to take it to the shop for regular maintenance, and will see what they find(As I'm not too involved with mechanics lol). Just to be clear though, the car runs perfectly, and drives normally.