Fuel pressure fault code

[JmRS4]

Was driving to work this morning and car starting idling rough at the traffic lights. Thought it may be a coilpack which had give up but after plugging laptop in I got the following code. Anyone had this?

[TomRS]

I'd say it will probably be the regulator within the HPFP thats failed causing high pressure thats the easiest place to start, but i'm not 100% still learning these motors!

[SuprSi]

I was thinking about this last night, do you think a block or stuck injector could cause this code? Either a stuck injector or regulator as Tom said would cause the rough running.

[JCviggen]

I was thinking about this last night, do you think a block or stuck injector could cause this code?

No, it's going to be in the HPFP area.

[JmRS4]

Thanks for your replies. Had it to my mechanics today and his diagnostics identified it as a misfire on cylinder 3 so he fitted a new coil which sorted the problem. Took it out for a drive tonight and it cut out but started straight away again. The epc light was on permanently on the way home however. Got laptop plugged in to find faults I'd never heard of so I reset them and car won't even start now. The fuel doesn't even prime when ignition is turned on, does that sound like it may be intank pump.?

[ArthurPE]

I had the same code
Fuel pressure sensor on the rail
Rear of the engine
Sensor is cheap
5 minutes to replace
Get the crush washer too

http://www.jlosee.com/images/RS4/PDF/TS ... essure.pdf

[TomRS]

Thanks for your replies. Had it to my mechanics today and his diagnostics identified it as a misfire on cylinder 3 so he fitted a new coil which sorted the problem. Took it out for a drive tonight and it cut out but started straight away again. The epc light was on permanently on the way home however. Got laptop plugged in to find faults I'd never heard of so I reset them and car won't even start now. The fuel doesn't even prime when ignition is turned on, does that sound like it may be intank pump.?

Misfire could be caused by the fuel pressure being too high, I wouldn’t have thought a coil pack on its own would cause a high fuel rail pressure, it would just cause a miss.
So the car drove fine until it cut out? Engine cut out I would assume be a safety shut off especially if the EPC light is illuminated.

Can you remember what the faults were? Or did you write them down?
You need VCDS plugging in read/post faults here and check the channel data for what your low pressure fuel pump is doing during cranking.

Does the fuel pump prime when you open the driver’s door? Should be a short 1 second burst from the low pressure pump upon opening the door.

[JCviggen]

I had the same code
Fuel pressure sensor on the rail

I had that same sensor replaced once, though I didn't notice any issues beforehand. If the sensor is sending garbage data to the ECU I can well imagine it not running right or possibly refusing to run at all for the protection of the system.

Cheap quick fix, worth a try.

[JmRS4]

Will plug laptop into it again later on and post results up. It was something to do with no Ecu signal and something to do with throttle. Can't hear the fuel pump at all when opening door or turning on ignition. Thanks again for your replies.

[TomRS]

I had that same sensor replaced once, though I didn't notice any issues beforehand. If the sensor is sending garbage data to the ECU I can well imagine it not running right or possibly refusing to run at all for the protection of the system.

Cheap quick fix, worth a try.

Thats a low pressure sensor reading your on about? that would either be the low pressure sensor (high side)/jammed open injector (had that myself) or bad low pressure pump/blocked filter.
This was for pressure too high which could still be the sensor but usually when they fail they read "low" it could also be (more likely) the regulating valve on top of the HPFP

I mean if there was no other issues (below) then i'd say throw one on for the sake of what they cost but it seems far more serious.

Will plug laptop into it again later on and post results up. It was something to do with no Ecu signal and something to do with throttle. Can't hear the fuel pump at all when opening door or turning on ignition. Thanks again for your replies.

Yes please do mate, sounds like your having ECU communications issues if its flagging up ECU singal error codes but we'll know more when you post up your errors so dont worry just yet!.
Throttle position would also cause the car to run rough and jerky plus it would cause the EPC but that alone wouldnt cause your lack of fuel pump prime etc and it would stil lallow the car to start.

[JmRS4]

Plugged laptop in to find the following results.




No mention of the fuel pressure now?

[coffey555]

How old is your battery? I had a load of random sensor errors last month that all went away after fitting a new battery.

[JmRS4]

Got a receipt for it being replaced last October, checked that and it looks a good un. It's just turning over, missing the sound of that v8 rumble now!

[ArthurPE]

The TSB I linked says it could fail high or intermittent
From the other codes hard to guess

[ArthurPE]

Most sensors in automotive apps are direct acting
Meaning the signal/current goes up as the measured variable increases
Resistance (or capacitance depeding on type) goes down as pressure goes up so more current flows

If the sensor has failed or shorted it may draw too much current and drag that buss V down

Try this
Pull the connector off the sensor and see if the other codes clear