Dpf regen throwing up code P0087 fuel rail/system pressure is too low.

G

gaz_123

Member
Has anyone else had a similar issue and has anyone found the problem. T6 everytime it regens the coil light flashes even though it completes the regen, code is P0087 fuel rail/system pressure is too low.
Garage inspected it and fuel pressure isnt low and its running perfectly, no leaks on the fuel rail or anywhere. All 4 injectors were replaced a month ago so its not them plus had a new fuel filter a month ago. So we replaced the fuel rail sensor but still this issue persists. Fuel pump is fine has no swarf and is not suspected to be failing. Dpf is clean and unclogged. Van is perfect apart from everytime it does a regen. Anyone else have this issue? No loss of power or anything!
 
Any access to vcds for a full scan?

I think we will be a better diagnostic report to work with.

The fuel pressure valve and sensor is on the fuel rail.
 
No sorry but the garage is a vw specialist and said everything is working at the perfect pressures even under heavy load when driven so they dont have a clue as nothing in the fuel system is giving them any clues. Just that it only logs the code intermittently when the dpf has finished its regen. When you turn it on and off the codes disappears until the next time it does a regen? They are baffled as even the dpf seems to be working as usual
 
If they have no idea....

Then you need to take it to a different garage for a second option..... They must have missed something.

The fault codes are logged for a reason.

If they are VW guys they will 100% have VCDS and that will give a very detailed report, that could be used to get more background info to try and narrow down the fault.

Another option is to book it into VW and pay for a diagnostic session - see what they come up with?.... They would have seen the same issues before and possibly know where to look.
 
Lewisgeorge said:
Did you get any answers for this mate?
My van does the same thing but also misfires and once the regen is complete it’s all fine.
Click to expand...
had the hpfp replaced yesterday, and its driving better then ever before so i was hopeful it was all sorted but then today after driving 165 miles coil light and same low fuel pressure code p0087 came back! Next steps is the fuel rail and fuel regulator however we are not getting any symptoms apart from high idle at the time it happens, runs perfect apart from this dam light and code!
 
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UPDATE - the whole of the fuel system has been replaced including the fuel tank, lpfp, hpfp, fuel rail, fuel regulator, fuel pressure sensor, fuel filter, all 4 injectors due to fuel contamination and swarf being present in fuel tank and still the p0087 code! Scan is still showing 300-400 loss in fuel pressure however van drives perfect, seems to throw the fault code every 150 miles when going around 60-70mph. The van was remapped prior to our ownership so unsure how well thats been done so at this monent in time the remap is being reversed back to factory settings, fingers crossed as we are £6.6k down and still no solution!!
 
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*UPDATE* so after replacing the whole fuel systems including the tank the code still resurfaces so couple of weeks ago had the remap reversed (was done before we bought the van 150bhp to 180bhp) drove even better then before less agressive in the revs but no obvious loss in power just a smoother rev count - got 300miles and light came back on code p0087 still. Drove to devon on holiday absolutely perfect except when we tried
To go up a steep hill. Light came back on but now 2 codes appeared P0087 low fuel pressure and also p0562 low voltage! In the past 6 months we have also had this accompany the p0087 code but not everythine and not for a while. Battery and alternator seems fine apart from if we leave the battery a day it goes down to 12.1v so unsure if its a sign of a weak battery or alternator. Vans back in the garage next week to check out the wiring and alternator - wish us luck hopefully we have found the trigger
 
ANOTHER UPDATE*** whole fuel system now replaced how ever we now have a reader, van has been low on fuel all week so filled it again, shortly up the road van goes in to high revs, reader states its in active regen, so when we get on a faster road i out my foot down and straight away the p0087 code returns, van into limp mode and regen stops. Now and again along with the p0087 code we get a low voltage code p0562 so we have been monitoring the voltage, fuel pressure and regen at the time the fault kicked in. I will add the graphs below but excuse the number as the app we are using will only let us display 2 things against each other
 
Does anyone think the intermittent voltage dropped is happening first from these graphs? Or is it impossible to tell? Only the p0562 code comes on sometimes with the p0087 code and when this happend last week the low voltage didnt come on at all. To add at no time has any dpf code come on
 
seems to throw the fault code every 150 miles
Click to expand...
That might indicate the fault shows whenever van does a regen.
If your fuel tank was less than 1/4 full, then it won't regen - which in a way could be a troubleshooting measure - but can also lead to problems.
So - could troubleshoot it by timing it so that if you drive it for 130ish miles - making sure the tank is less than 1/4 full. drive it for another 30 or 40 miles. It won't regen but you can see if the fault appears.
Can you check soot/ash residue etc using a Carista/VCDS etc?
I'm not a mech so only going on what I've read in these forums.
 
whodat said:
That might indicate the fault shows whenever van does a regen.
If your fuel tank was less than 1/4 full, then it won't regen - which in a way could be a troubleshooting measure - but can also lead to problems.
So - could troubleshoot it by timing it so that if you drive it for 130ish miles - making sure the tank is less than 1/4 full. drive it for another 30 or 40 miles. It won't regen but you can see if the fault appears.
Can you check soot/ash residue etc using a Carista/VCDS etc?
I'm not a mech so only going on what I've read in these forums.
Click to expand...
Yes the reader we have stated it was in active regen when this happened twice now and also the soot leveks were near 30g so it was trying to do a regen then this error stopped ot as somethings causing the low fuel pressure when in regen only, whole fuel system is new so our only indication is the voltage drop causing the drop in fuel pressure which in return is making the dpf regen cut short, well thats what we are thinkng at the minute as the dpf isnt blocked
 
gaz_123 said:
Yes the reader we have stated it was in active regen when this happened twice now and also the soot leveks were near 30g so it was trying to do a regen then this error stopped ot as somethings causing the low fuel pressure when in regen only, whole fuel system is new so our only indication is the voltage drop causing the drop in fuel pressure which in return is making the dpf regen cut short, well thats what we are thinkng at the minute as the dpf isnt blocked
Click to expand...
Hey, did you find the cause to this issue in the end?
 
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