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BMWx3 EGR code p0401

Discuss anything to do with the (E83) BMW X3 here
(Older F25 discussion within will ideally to be moved to F25 Sub section below)
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wizard-58
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BMWx3 EGR code p0401

Post by wizard-58 » Wed Jun 15, 2022 12:58 pm

HELLO everybody newbie to this forum but been an BMW x3 owner for a little over 7 yrs .like most people who join these forums where all looking for ideas and advise but I am really having issues and hope someone can suggest something I and many others havent thought of or tried yet .
I have read so many posts but can not find my problem any where .
I have a 2007 2.0d with m47tdu2 engine .
I service and repair the car my self but I am here with a problem that I cant solve and hopeing that somebody on here may be able to help .
I have 3 different kinds of code reader a cheapo .torgue pro on my phone and Inpa ( al but in german .)
my problem is the dread p0401 low flow egr reading .
I have in the last 6-8 weeks removed and cleaned as best as possible the inlet manifold ( no swirl flaps present ) refitted with all new gaskets .fitted new MAP sensor .new exhaust temperature sensor ,new dpfe sensor ,new egr valve ,new egr solinoid .new egr cooler pipe. new turbo pipe temperature sensor. and every time i get the same code back p0401 ..i also get a missfire jolt sort of feeling at low rpm 1200-1500..if i unplug and block the EGR vacuum pipe car runs and performs as normal but I still have the code .
Ive been quoted £250.to have my engine remapped and the egr mapped out at the same time but Im a nervous of doing that .
Ay advise would be appriciated .cheers

wizard-58
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BMWx3 EGR code p0401

Post by wizard-58 » Wed Jun 15, 2022 3:17 pm

hi just a quick update decided to try a different route this afternoon and unplugged the MAF but left the EGR all connected ..drove the car and as expected codes for MAF .p0101 p0112 .1st is the maf low voltage generic code and the second is IAT .BUT NO p0401 so is the maf causeing said problem ?? ill update later as ive got a replacement ( only cheap generic one ) ill see if it gives me different codes or ??

wizard-58
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BMWx3 EGR code p0401

Post by wizard-58 » Wed Jun 15, 2022 3:59 pm

ok another update fitted MAF and cleared codes ..drove car and got p3264 turbo hose off?? i am assumeing that was because i removed it to get t MAF ..car drove fine no problems untill i got back .cleared p3264 code and when cleared car judderd and up popped the dreaded p0401 got to give up for today hope to get another go at her at weekend ...still anybody got any suggestions ill be happy to listen .somebody else must have gone through all this before .. :headbang:

Leslie
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BMWx3 EGR code p0401

Post by Leslie » Wed Jun 15, 2022 8:41 pm

HI and welcome :hi: the fact you unplug the blank off the egr and it runs fine suggests you are getting egr all the time and too much for the engine to run right . The maf is important in the loop and even on a cheap code reader you should be able to view the airmass and see it drop with the live data if you plug and refit the egr vaccum pipe . If the value is not changing at all that could point to a maf fault . Id do a search on here as there was someone with egr trouble recently :thumbsup:

Just a thought is it possible to fit the pipes to pressure converter wrong way round so you are getting vacuum all the time ? Can you feel vacuum at idle on the pipe ?

are you talking about the hose from airflow meter to front of turbo as if it was off the airflow meter would be reading nothing ?

wizard-58
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BMWx3 EGR code p0401

Post by wizard-58 » Fri Jun 17, 2022 3:15 pm

Hi Leslie and thank you . with engine on idle there is vacumm all but quite low .im going to plug in my lap top to the car over the weekend I have inpa on that and it will give me the live data feed .
it is possible to fit the vacumm pipes the wrong way round on the solinoid but i fitted as directed and it was the same way around on the original ( dont even know if original had a fault )
yes the hose from maf to front of turbo i figured i got the code for that when i removed it to get at maf that has been cleared now as have all other codes except the p0401 ( egr flow insufficient deteted ) this code comes up whether the vacumm is conected or not :headbang:
I am also going to do a forced regen hopefully over the weekend maybe thats causeing somesort of bad pressure reading but im only clutching at straws .

Leslie
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BMWx3 EGR code p0401

Post by Leslie » Fri Jun 17, 2022 8:02 pm

One of those problems that could be caused by many things , you should be able to see the back pressure in the dpf and the soot mass which will hopefully tell you if the dpf is loaded up or partially blocked :D The egr is I believe important for regens but I don't know enough to know why . Some egrs have a throttle valve fitted too that can stick or the return spring fail but I don't know if yours had that or not :D

wizard-58
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BMWx3 EGR code p0401

Post by wizard-58 » Mon Jun 27, 2022 9:52 am

Hi just a quick update .no change still getting same code have not attempted force regen yet as been busy ..car is driving fine with EGR vacumm pipe discneccted and plugged ..im going to start again checking all old parts and refitting just to rule out faulty new part .

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marti
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BMWx3 EGR code p0401

Post by marti » Wed Jun 29, 2022 5:30 pm

Are you get black smoke out of the rear upon acceleration?

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