# Mysterious Low Pressure EGR Issue



## Toothdoc383 (Jul 31, 2016)

Hello Everyone,
I have worked on many diesel light duty trucks older and newer but the BMW diesels are completely new to me. I have a 2012 X5 diesel that has had no troubles for 60k miles. Not long ago, the check engine light came on. No drivability problems whatsoever though. Dealer pulled P045 code. Low pressure egr was replaced along with some vacuum lines. Light came back on after about 30 miles. Light will go back off only to come back on after another 30-75 miles of driving. No pattern at all as to driving conditions or temperature. Vacuum pump also replaced by dealer. They said the egr vac control valve is functioning properly but I think they are clueless as to where to go next. They dont mind of course throwing parts at it until the problem goes away. I am wondering if the charge air intake sensor could be a possibility since the egr system depends on this information. Any help would be greatly appreciated. Thanks


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## Doug Huffman (Apr 25, 2015)

P0455 or P0456 or not enough digits?


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## Toothdoc383 (Jul 31, 2016)

P045e was the generic one I pulled. BMW got the same thing but I need to pull the invoice to see what the BMW specific code was.


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## Doug Huffman (Apr 25, 2015)

There should be a test plan available.

http://www.bmwmotorsports.org/BMW_docs/understanddiags.pdf


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## Hoooper (Jun 17, 2013)

You sure it wasnt P0045 for turbo boost control? All of the P045x codes are evap codes, we dont have an evap system. If its P0045, they should first run a smoke test to check for boost leaks.


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## Toothdoc383 (Jul 31, 2016)

Thanks for the replies. I pulled the paperwork and realized I had posted the codes incorrectly. They were 47c4, 478e, 478f. Now, those codes are gone it is giving a 40d4. They said it is insufficient flow on the low pressure egr. They claimed that even when operating the egr manually, it still gave the same code. Now they think that the egr cooler for the low pressure egr is partially clogged so there is insufficient flow through it. Sounds reasonable I suppose but here is my problem with it. The exhaust going through the low pressure egr valve has already passed through the dpf so how on earth could there be enough carbon going through the cooler to clog it up with carbon? They said there is a procedure to clean it but I would rather put a new one in if this is in fact the problem. The car runs perfect, mileage is the same. Check engine light comes on and goes back off after driving for awhile. Car is driven frequently on the highway. After my experience with dpf trucks, I make sure it gets driven hard on occasion to help keep it happy. I love the car but I would like to get this figured out soon. By the way, this all started 1500 miles after the warranty expired. Figures, right? Any thoughts would be appreciated.


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## standa (Mar 5, 2014)

Buy enet cable, download Rheingold and if you have some skills you will not need your stealer.
Here I would recommend deletion of adaptation values of EGR, it throws errors even after replacement of some parts connected with EGR.


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## smassey321 (Feb 5, 2007)

Rheingold is what I used when I solved my EGR issue that the dealer could not. It is a code reader, test plan, diagnostic and factory service manual all rolled into one. I think the adaptions are only for the HP EGR. I also replaced my charge intake sensor attempting to solve my issue. The new part was defective and that completely confused me for a coupe of months until I figured it out. So don't assume your new LP EGR is good out of the box. You may want to remove the cooler and visually inspect. Is dealer paying for parts swaps?


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## Hoooper (Jun 17, 2013)

Classic carbon buildup in the manifold and intake runners issue. You get EGR insufficient codes even though the EGR itself is fine. Do you make lots of short trips with this X5?


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## Toothdoc383 (Jul 31, 2016)

The dealer is not paying for part swaps. The car gets driven about 60 miles per day, most of which is over 50mph. Gets frequent hard accelerations due to pulling onto highways. I considered the charge air temp sensor because I have read about them causing multiple issues. Car is going in on Friday to have the lp egr cooler removed. I am going to look at it before they replace it. I still don't get how post dof exhaust can clog the cooler to the point of reducing flow.


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## smassey321 (Feb 5, 2007)

I spent 8 months trying to fix my odd EGR issue. Ultimately it was caused by old software which I doubt you have on a 2012. Since you have already checked out the vacuum lines the next logical things are to check are CBU (as Hooper said) and MAF (air mass meter). Sensors usually throw a code so don't waste a lot of time on those like I did. MAF can be out of spec and confuse the EGR system. This is a long shot but ask your dealer about SIB B13 06 16. That is new bulletin related to the MAF.


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## Toothdoc383 (Jul 31, 2016)

I think I got it! Vaccuum control valve and yet another vaccuum line. I think Kea uses better vaccuum line material than BMW! No light so far. If it comes back on, i will know because my wife will trade it in before I see it again. Thanks for all your help. We will see if this is it.


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## Kostyan (Aug 8, 2014)

OP - I got exact same three codes as you were initially and wondering if they ever came back after replacing vacuum line and vacuum control valve. Did you fix this on your own or had dealer do it?

Wondering if there are any write ups on how to replace this on your own.


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## panzerI (Apr 28, 2020)

Verify that your reader isn't throwing a DME 4530 and 4873. I had the same issue as you did with random reduced engine power with a check engine light. I personally replaced all vacuum lines, vacuum controllers, still same problem. I eventually got a vacuum tester and started checking all the valves. Low and behold, the front EGR vacuum valve was not holding pressure, thus not allowing the EGR to open and close. Spring was perfectly fine, but because of hot gasses being trapped, you got a reduced engine power. The valve is directly under the EGR cooler. I had already cleaned MAS, EGR, etc... The part number is BMW 11-71-7-796-883 1 Pack Vacuum Box. Hope this helps.

https://www.amazon.com/BMW-11-71-7-...=1&keywords=11717796883&qid=1590857270&sr=8-1

Attached is an example of where the EGR Valve is located. Hope this helps.


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## sk72 (Jan 5, 2016)

I had the same error code 00478F, 00478E, and 0047C4 yesterday driving back from a 70-mile trip. I use Carly to detect faults. 
While driving back home I saw an Engine malfunction (low power ..)message on dash, then after 40 miles, CEL light came on. I ran diagnostics via Carly and I now have 00478F, 00478E and 0047C4 error codes. EGR cooler was replaced earlier last year (Jan 2019) and I believe I have a 2-year warranty on this part. 

Should I clear the codes (if this is even possible) and wait if CEL comes on again? For the last 6 months, I have been driving short distances. Could this even be related to carbon build-up? 

Will this repair be covered under the EGR cooler 2-year warranty from the dealer?

Thanks.


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## sk72 (Jan 5, 2016)

sk72 said:


> I had the same error code 00478F, 00478E, and 0047C4 yesterday driving back from a 70-mile trip. I use Carly to detect faults.
> While driving back home I saw an Engine malfunction (low power ..)message on dash, then after 40 miles, CEL light came on. I ran diagnostics via Carly and I now have 00478F, 00478E and 0047C4 error codes. EGR cooler was replaced earlier last year (Jan 2019) and I believe I have a 2-year warranty on this part.
> 
> Should I clear the codes (if this is even possible) and wait if CEL comes on again? For the last 6 months, I have been driving short distances. Could this even be related to carbon build-up?
> ...


UPDATE:

Dealer suggests the replacement of pressure converter (11747805391) and hose vacuum (11747797129) and an estimate of $1237 (parts and labor). They declined my request to be replaced under emission warranty (10 yrs/120k miles).


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## ntxdvr (Aug 25, 2020)

Toothdoc383 said:


> Hello Everyone,
> I have worked on many diesel light duty trucks older and newer but the BMW diesels are completely new to me. I have a 2012 X5 diesel that has had no troubles for 60k miles. Not long ago, the check engine light came on. No drivability problems whatsoever though. Dealer pulled P045 code. Low pressure egr was replaced along with some vacuum lines. Light came back on after about 30 miles. Light will go back off only to come back on after another 30-75 miles of driving. No pattern at all as to driving conditions or temperature. Vacuum pump also replaced by dealer. They said the egr vac control valve is functioning properly but I think they are clueless as to where to go next. They dont mind of course throwing parts at it until the problem goes away. I am wondering if the charge air intake sensor could be a possibility since the egr system depends on this information. Any help would be greatly appreciated. Thanks


I had similar problem on my 336D. First the vacuum lines, then EGR cooler, and now Massive carbon buildup


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