BEW PD EGR fault low power after initial takeoff P0403 P2413

so I just fixed a low power issue on my BEW PD 04 golf that i bought, turned out to be the tandem pump. my other daily driver formerly known as the "good" BEW PD 04 golf i guess got jealous from all the attention and now is running horribly.

codes thrown are PO403 and P2413. resetting codes on scanguage or vagcom makes car run great for about 4-10 seconds and then low power returns and codes are shown "pending" on scanguage or present on vagcom.

Parts swapped with bew that is running well:

MAF sensor no change.
EGR valve no change.

other actions taken:

unplugged EGR. runs the same.

changed fuel filter. no change.

EGR duty cycle on block 003 of vagcom shows 100.6 percent all the time period. unplugged, plugged in doesnt care.

Air box cleaned, pulled off grommet to make sure it didnt have clogged screen causing problem. no change. MAF swapped with known good one, no change, EGR cleaned, no change. swapped with good one no change, unplugged, no change.

MAF reading is weird on vagcomm. sometimes it is is more than specified sometimes less than specified. when you clear the two codes it runs like a scalded cat for about 3-10 seconds sometimes a bit more and then loss of power returns and seems like it is sort of in limp mode but not quite.

boost sits around 8 -10 psi until you clear code then it shoots up to normal 15 till loss of power happens 10 seconds or so into the run and drops back to 8 to 10 or so. not really limp mode...kind of like partial limp mode. resetting code fixes it every time for about a few seconds as described.

only code it throws are P0403 and P2413.

no smoke, it is not fueling it purposefully it seems. checked actual and specified boost on vagcom it matches perfectly in or out of low power. it just drops amount specified when the problem occurs.

once in a while after a run on the highway with lowish power at 70 mph or so but no umphh in it boost stopping at say 8 - 10 psi i will roll up to a stop sign and suddenly have no power at all, i mean none, engine stumbling at idle just zero power, after a bit of cursing slapping and checking and flooring it in neutral suddenly revs up and goes. this is more unusual than the other problem which is very consistent.

still only codes thrown are P0403 and P2413. very frustrating.

I am under the impression that egr stuff cannot affect power just set codes. what am i missing.


again, MAF and EGR valve both swapped. no change, only way to get power back is to restart it or clear codes and it returns as soon as you get on it. no overboost codes.

any advice on how to proceed appreciated.

occasionally p0407 as well. same deal. messed with it today some more. cleaned grounds under battery, checked connectors cant see any problems.

start the car and go runs great for a bit first time, when you slow down and then try to go again bam right into the wall of no power.

check vagcom and it will be P0403, p0407 and/or p2413. clear codes and it will run with power for the 4-10 second run or so and then lose power again. and of course the code will have returned. usually the signal low egr one.

checked vacuum line to turbo and it holds good vacuum, actuator moves fine.
i really dont think it is air problem in the typical sense because there is NO smoke i mean none. every turbo problem i have had results in clouds of smoke.

weird part is when it starts acting up the actual and requested EGR on vagcom never goes above 550 or so REQUESTED. the ACTUAL goes up and down with vehicle and engine speed. might be as high as 800 to 900 but REQUESTED is stuck at 450-500.

however at IDLE the requested is say 250-300 and the ACTUAL is about 450 which seems a bit high but i have never paid it much attention before at idle. when you go and it has initial good power the actual requested will match in the 800-900 range or rather the requested will be 850 and actual will be a bit higher but when the code sets the requested drops into the 500's and stays there while the actual fluctuates up and down based on engine rpm and vehicle speed as i am guessing it should.

any ideas why this would be happening. what would cause the car to request less than it clearly needs and wants? this is really new kind of problem for me and like the arrival of most problems at a rather inconvenient time.

any advice help on requested vs actual and reasons it would be running low requested with corresponding low power will be very helpful to me.

again, i have replaced the maf with a known good one and driven the other car with this one's maf, it is not a sensor problem. as to wiring i have not done much since it runs normally when the code is reset albeit briefly till code sets again. seems to imply the maf and related wiring is good but again i am sure open to ideas.

ok. so wish i had a how i fixed it follow up but problem is gone. i reseated and played with all the egr plugs, checked the intake for leaks, didnt find any. reseated and cleaned the turbo vane position plug based on some other thread i found, checked the voltage on the MAF wiring since i already swapped the MAF, reseated and cleaned the N75 and what i believe was the N18.

left EGR unplugged and went for a drive, ran fine, set code for egr unplugged of course. ran it again, and again and now on like 250 miles no problems. runs good, plenty of power, requested MAF back up where it should be. still has egr code and currently i dont care.

after about another week i will plug it back in and see how it runs. guessing it will be fine since unplugging it the first time did nothing, it still ran like crap and kept setting codes and would run fine for about 5-10 seconds after clearing code and then mess up again, plugged or unplugged....

dont have time to have it running poorly right now, lots of other projects on the table but like i said i will plug it back up in a week or so when i have time to mess with it and when i verify it is indeed going to run ok albeit with a code. then i can try to see if it comes back plugged in and troubleshoot it some more.

wish i knew what made it run better. something i reseated leaning towards that plug on the turbo...hard to say. if i was a shop this would have been a waste of 4 hours that i could not charge for since i have no idea what i did or when it will return.

just wanted to update in case it is of any use to anyone else. first problem this bew has ever given me, straight out of the blue as most problems usually are i guess