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
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BMWx3 EGR code p0401
BMWx3 EGR code p0401
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 ??
BMWx3 EGR code p0401
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 .. 
BMWx3 EGR code p0401
HI and welcome 
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 
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 ?
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 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 ?
BMWx3 EGR code p0401
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
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 .
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
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 .
BMWx3 EGR code p0401
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 
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
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 BMWx3 EGR code p0401
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 .
BMWx3 EGR code p0401
Are you get black smoke out of the rear upon acceleration?
BMWx3 EGR code p0401
Hi there Marti I do get black smoke but its not regular ..if im coming to a junction for example and i drop down a gear 4th- 3rd say then ill get smoke as i throttle back and re acelerate . I havent noticed it under normal accelerating conditions ?? have plugged in lap topthiss morning and inpa is giving me code 4501 ..exhaust gas recirculation control,control deviation ..further down its saying airmass too high ..I have to translate this from german script as my inpa wil not give all information i english ( have tried may times to fix) any ideas would be gratefully recieved .
BMWx3 EGR code p0401
I had loads of problems with my X6....turned out to be just the MAP sensor and it wasnt giving any codes for the MAP, black smoke as yours, dpf light on etc etc.....
Map sensor situated on the side of the intake manifold.....
Map sensor situated on the side of the intake manifold.....
BMWx3 EGR code p0401
Hello again Marti and thanks for that .I did replace the map sensor when i first had the problem back in april same time as i did a sort of inlet manifold clean ( bit of a scrape out ) .Ive replaced numerous other parts as is described earlier . Ive had a few personal things to sort the last few weeks so havnt had much chance to delve any deeper . Ive booked a few days off and intend to go back and remove the manifold again and do a proper clean .whilst it is off i will check all vacumm pipes that are hiiden away underneath as the map sensor is an easy get to ill refit old one and try again hope fully by refitting old components and going through it in stages ill trigger a different code or something that will give me some indication ..maybe it is a bloody faulty new map ( proberbly the cheapest bit ive replaced ) again i apreciate any thought s or suggestions matbe some one will just come up with something ive totally over looked .thanks again .
BMWx3 EGR code p0401
Is the map sensor you fitted genuine?
BMWx3 EGR code p0401
no it is generic one so its possibly not a good one ill get a genuine one and fit it when i do the manifold .
Ive oredered a few mtres of silicone hose as well going to change all the vacumm hoses whilst the manifold is off saves having to worry about them .
Ive oredered a few mtres of silicone hose as well going to change all the vacumm hoses whilst the manifold is off saves having to worry about them .
BMWx3 EGR code p0401
BREAKING NEWS . have just removed Manifold and egr etc to do thourough clean and chnge all vacumm hoses .before final removal noticed very wet/oily at rear of manifold when removing rear lower (square ) manifold gasket was damaged infact it had fallen out not sure if was even in place before i removed manifold it is actually split in halve and looks like it has been seriusly leaking how it has even run all this time is beyound me but im hopeing this is cause of all my troubles .new one wont arrive till tuesday but ill be giving it agood clean and will update when i reassemble everything .( i did replace them all when i had the manifol off earlier in the year ) it proberbly dropped when i was reassembling ??
ill stick them in this time with a bit of silicon .
ill stick them in this time with a bit of silicon .
BMWx3 EGR code p0401
Let’s see if that finally gives you the answer. Fingers x’d 
Never anthropomorphise computers. They hate that.