Intermittent P0087 on 2011 JSW TDI 160k miles, haven’t been able to pinpoint problem

[Captain Touchdown]

Hello all,

I’ve been a longtime reader of the forums as I fix odds and ends on this vehicle I purchased from a local used car lot in 2020. No clue what the maintenance history was like, it sat on the dealer’s lot for over a year and was picked up at a big auto auction. I don’t know what the status is of the emissions fix, but I assume any warranty associated with that would be expired.

I’m having a fuel issue that I’m having trouble figuring out. I am getting intermittent P0087 low fuel rail pressure codes and the vehicle drops into limp home mode. Sometimes every 10 miles, sometimes I’ll go 100 miles without it. There’s also a hydraulic-sounding whine coming from under the hood when it happens. I actually thought it was a failing power steering pump the first time I heard it due to the specific sound. However the sound does not change in pitch when turning the steering wheel or raising the throttle.

If I pull over and let the car rest for a minute then restart the engine and start driving it is completely normal until the next time it throws the code. I’ve taken to using my basic Wi-Fi ODB code reader (I don’t have VCDS) to reset the fault codes when it happens so I don’t have to pull over and wait to restart the engine. Doing it this way doesn’t seem to have any affect on how often it happens. My anecdotal experience is it happens more often in the heat, but I also don’t drive it out of town much in the winter so that could also be the reason I notice it less.

After searching the forums and looking around online extensively I’ve done the following:

First, I replaced the fuel filter and found no metal shavings and no other debris.
Second, I replaced the fuel metering valve on the HPFP and checked for metal shavings in the HPFP. Also no debris there.
Third, I have tried tracing the source of the hydraulic whine and it seems to be emanating from one of the lines coming out of the fuel filter.

At this point, I’m not really sure what to do. None of the posts I can find mention any kind of noise like I’m hearing. It doesn’t seem like an HPFP failure so I don’t want to go through the labor and expense of replacing it unless that’s almost certainly the problem. I’ve heard about restricted fuel flow causing issues, but I’m not sure how to diagnose that.

I would appreciate any kind of troubleshooting tips you can offer, and I would be happy to provide more information if it would be helpful. Thank you!!

 

[oilhammer]

First, there is no power steering pump... that car uses an electric assisted rack, so you can rule that out.

Second, have you placed your hand on the electric fuel pump (the auxiliary pump) under the hood and felt if it was vibrating badly and perhaps the source of your noise? It's in a rubber mounting in a metal bracket right up top near the coolant bottle. It could be failing, OR, the electric lift pump in the tank could be failing and starving the aux pump for fuel.

That would be my guess from your DTC and your description.

 

[Captain Touchdown]

First, there is no power steering pump... that car uses an electric assisted rack, so you can rule that out.

Good to know, thank you!! I had no idea.

Second, have you placed your hand on the electric fuel pump (the auxiliary pump) under the hood and felt if it was vibrating badly and perhaps the source of your noise? It's in a rubber mounting in a metal bracket right up top near the coolant bottle. It could be failing, OR, the electric lift pump in the tank could be failing and starving the aux pump for fuel.

The sound is coming from exactly that area! Let me reproduce the issue and I’ll report back soon. Thank you so much.

 

[oilhammer]

That aux pump is a Bosch unit, and can be found by searching for the Bosch long number 0-580-464-121. Volkswagen will just sell the whole assembly, which is 5N0-906-129-B but it costs more and so long as nothing is broken in the mounting you can just change out the pump itself.

But the in-tank unit is best serviced as the whole assembly, access panel under the rear seat. Pierburg, Siemens-VDO, or Bosch supply those. The OEM number is 1K0-919-050-AB.

 

[Realcamogirl]

Did you solve this problem? I have the exact same issue with my 2012 Jetta.

First, there is no power steering pump... that car uses an electric assisted rack, so you can rule that out.

Second, have you placed your hand on the electric fuel pump (the auxiliary pump) under the hood and felt if it was vibrating badly and perhaps the source of your noise? It's in a rubber mounting in a metal bracket right up top near the coolant bottle. It could be failing, OR, the electric lift pump in the tank could be failing and starving the aux pump for fuel.

That would be my guess from your DTC and your description.

 

[Captain Touchdown]

Did you solve this problem? I have the exact same issue with my 2012 Jetta.

I’m so glad you responded, I’ve been meaning to update and I keep forgetting to log in and write it up.

The problem is not solved. I ordered a replacement aux fuel pump and replaced it. The hydraulic-sounding whine was definitely coming from the area of the aux fuel pump, and I‘m fairly certain that it’s the only thing in that area that could produce the sound I’m hearing. However, the new aux fuel pump is making the same sound and I’m getting the irregular P0087 codes.

Performance is about the same as before, I don’t think having the new pump has made a difference one way or the other. When I first replaced it, I felt like it was somewhat better but I don’t believe that any more now that I have some more miles on it. At this point, I’m not sure what to do. I’ve seen some videos on how to diagnose a fuel restriction and I’m going to try going down that road. Perhaps there’s a fuel restriction in the tank or the lines that is causing the aux fuel pump to struggle and start vibrating/making noise??

Sorry to hear you’re having the same issue, good luck to you on fixing it. Hopefully somebody has a few suggestions for us to try.

 

[Captain Touchdown]

Checking in to ask for some more assistance. The new aux fuel pump is still making the same noise. I took the vehicle for a highway drive after work today and it was popping P0087 codes every few minutes and even started to cut out a little bit before I turned back toward town. I stopped to turn the engine off for a bit and it made it back to town without cutting out.

What is the purpose of the aux fuel pump and what is the flow of fuel through it? I’m trying to work out how to look for some kind of fuel restriction.

 

[Tuheeden]

Ok, this will sound crazy but that system CAN run with the fuel lines to the HPFP pump reversed. If someone changed fuel filter and took the hoses off and mixed them up putting them back on, you would get issues like you are describing. I will look at mine in the morning and give you the hose mapping to verify

 

[Captain Touchdown]

You know, I did have the fuel filter replaced not long before this happened. If you could share some hose mapping information, that would be tremendously helpful. Thank you!

 

[Tuheeden]

You know, I did have the fuel filter replaced not long before this happened. If you could share some hose mapping information, that would be tremendously helpful. Thank you!

CJAAfuelflow.jpg

CJAA Fuel Flow

forums.tdiclub.com

CJAA

forums.tdiclub.com

Dont know if those links will work for you (I still cant figure out how to upload photos....)
However the CJA and the CBA hoses 3 & 4 (the 2 closest to the front of the car) are REVERSED and I have actually done this.
So from back/left to front right - hose 1 is input from fuel tank, hose 2 is output - return TO fuel tank, 3 is output to HPFP, 4 is input from fuel rail (fuel returning from the rail) - So if #3 and #4 are reversed, the car will run but will spit an error under any real load.

 

[Tuheeden]

Mine might look a bit different because I have a CP3 pump but the rest should look somewhat the same.

 

[Captain Touchdown]

I believe everything is hooked up correctly, but here’s a picture just in case. What do you think?

IMG_1134.jpeg

• Captain Touchdown
• Jul 28, 2023

2011 JSW Fuel Filter

 

[Tuheeden]

I believe everything is hooked up correctly, but here’s a picture just in case. What do you think?

IMG_1134.jpeg

• Captain Touchdown
• Jul 28, 2023

2011 JSW Fuel Filter

Yea that looks correct.

Usually the low fuel pressure code on the CP4 fuel pump is either the aux pump, a filter clogged or the HPFP is failing but I think you reviewed all of these options

 

[calimustang]

oh boy. have you checked the fuel tank? there may be mold/mildew or some kind of debris clogging that makes aux pump to work harder as theres not sufficient fuel flow?

I had the very same whining sounds back in 2018. 5 HPFP failures and 6 months later from 20k miles to 25k miles, the idiots at VW finally thought of checking the fuel tank and BEHOLD! it was caked in mold/mildew from car sitting during the buyback period of 2 years.

they covered it all and the very next day, I slapped the CP3 on and never look back, she chugs flawlessly at 171k miles now.

 

[Captain Touchdown]

oh boy. have you checked the fuel tank? there may be mold/mildew or some kind of debris clogging that makes aux pump to work harder as theres not sufficient fuel flow?

I had the very same whining sounds back in 2018. 5 HPFP failures and 6 months later from 20k miles to 25k miles, the idiots at VW finally thought of checking the fuel tank and BEHOLD! it was caked in mold/mildew from car sitting during the buyback period of 2 years.

they covered it all and the very next day, I slapped the CP3 on and never look back, she chugs flawlessly at 171k miles now.

I can finally report that the problem is solved!! It took a while to line things up correctly — I waited until I was critically low on fuel, I didn’t have anywhere to drive the next day, and the weather was nice. Finally in September the stars aligned and I was able to spend an afternoon opening the fuel tank and cleaning it out.

Before committing to opening it up, I put a pressure valve on the line coming from the tank to see what the tank pump was putting out. I don’t remember the nominal pressure, but it was about half that. So I went ahead with opening the tank and sure enough, there was a decent amount of debris in the tank pump. The little cup that the pump sits inside had a bunch of dark bits that looked like coffee grounds stuck in there as well as two chunks that looked something like a ball of cat hair. No clue what they actually were, just describing their looks! There was also some crud in the bottom of the tank.

To clean things out, I used a little hand pump to remove the remainder of the fuel from the tank as well as the fuel from the cup the tank pump sits in. With that done, I pulled the tank pump and did a full inspection. The fuel tank itself was easy to clean out, I used some shop towels to wipe the bottom and pick up the little bit of gunk that was there. The pump was trickier since it was down inside that cup. I settled on using some of the diesel I pumped out to swish around in there for 10-15 seconds, then quickly poured it into a bucket before the debris settled. That would carry out some of the debris each time. I had to do it eight to ten times before it was all gone. I didn’t want to re-use this fuel as it was pretty cruddy, so it became weed killer. (Apologies to mother earth.)

From there, I put the newly cleaned tank pump back in and re-set seal on the fuel tank. I was able to get through the whole process without dripping any diesel on my carpet, miraculously. From there I poured a two gallon can of fresh diesel in. I don’t have VAG Com or anything, so I just put the car inn ACC mode without attempting to start it about a dozen times. I had also double checked the fuel filter while I was doing the pressure valve at the beginning of the project, so I wanted to get the pumps to run as much as possible before attempting to start. Once I did turn the engine over, it took a couple tries but then it fired up and ran like a champ.

(Important note if you’re going to do the same thing I did: get a can of fresh diesel BEFORE YOU BEGIN! I had to bum a ride to the gas station to fill my can with diesel.)

I’ve taken the vehicle on some 120+ mile trips in the month or so since and it’s performed flawlessly. The whine from the aux fuel pump is gone and it runs beautifully. I can put it in sport mode and floor it, going from a stop to 70 mph without triggering a P0087 warning. Thanks for all the advice everyone!

 

[calimustang]

Awesome!!!!!! I'm glad you took my advice. glad there are nothing serious affected them from that unlike me.... now you can totally enjoy her as much as you desire. like one guy's famous quote even on his signature, "drive more, worry less".