# urea urea!



## jefflieb (Nov 19, 2003)

FIRST OFF, I LOVE MY 335D........Well the message came on about the urea fluid in the emmissions system for the second time. the first time it said that in 1000 miles the car would not start so get service, I did within a day or two, then two weeks later the message comes on again, now its 190 miles til the car will not start.....PUMA case opened regarding a nozzle being clog with crystalized urea that need to be replaced, the key reader showed no error message either time. What does the urea cost anyway, every 20k miles? Is this common?:dunno:


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## Flyingman (Sep 13, 2009)

DEF generally lasts about 15k miles, should match up pretty well with your oil changes.

As I recall it is metered according to fuel consumption, at about 1-3% of your fuel consumed, so it is not miles driven but fuel consumed. So actual DEF consumption can vary.

Folks have had problems with the fluid getting old and crystalizing, also there are two tanks, a passive (larger) and active (smaller) tank with a transfer pump between them. That pump may fail and your active tank goes low even though you have DEF still in the passive tank.

There have been a few other reported problems ranging from the dealership not properly topping off both tanks during initial fill or during service.

My position is the DEF should last same range as the oil. If not something is probably wrong.

DEF is relatively cheap to buy at most truck stops, etc...running about $3.0/gal or about that. The dealers are a lot more (comes in a special BMW bottle with applicator, you know). You can add it yourself if necessary.

For me it has been a non-issue as handled during scheduled services. No fuss, no mess.


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## Snipe656 (Oct 22, 2009)

I find it interesting that it says incorrect fluid added. I did not know it had a way to check the type of fluid within the system.


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## bayarea2007 (May 20, 2010)

I was told by my SA that X5d had a lot more problems on DEF than the 335d


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## Pasa-d (May 7, 2011)

Snipe656 said:


> I find it interesting that it says incorrect fluid added. I did not know it had a way to check the type of fluid within the system.


It knows through level sensors that there's fluid in the tank(s). It knows through NOX sensors that the fluid doesn't do anything (or does it less than expected) when injected into the exhaust. This is how they prevent you from just putting water in the tank.


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## Snipe656 (Oct 22, 2009)

Pasa-d said:


> It knows through level sensors that there's fluid in the tank(s). It knows through NOX sensors that the fluid doesn't do anything (or does it less than expected) when injected into the exhaust. This is how they prevent you from just putting water in the tank.


I read on two separate occasions where people claimed to have put something else in and had zero issues. Which is why I find that image and statement within it interesting.


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## montr (Oct 7, 2006)

Here is from training manual "ST810 - Advanced Diesel Technology Workbook.pdf":

Suitable Urea-water Solution
The SCR system is monitored with regard to refilling with an incorrect
medium. This monitoring function starts when refilling is
detected. Refilling detection is described in the section on the
SCR system.
Effectiveness monitoring of the SCR catalytic converter is used for
the purpose of determining whether an incorrect medium has been
used. An incorrect medium is detected if the effectiveness drops
below a certain value within a defined period of time after refilling.
A reversible fault is set in this case. If the fault is determined in two
successive driving cycles, an irreversible fault is stored and the MIL
is activated.
In addition, the warning scenario with a remaining range of 200 mls
is started.


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## Snipe656 (Oct 22, 2009)

I am not doubting that it does not do it. I just find it interesting from what others have claimed. Either the system is not all that effective at that job or some people are not being all that truthful.


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## bimmerdiesel (Jul 9, 2010)

Snipe656 said:


> I am not doubting that it does not do it. I just find it interesting from what others have claimed. *Either the system is not all that effective at that job or some people are not being all that truthful*.


Thats problem with forums. Atleast DIESEL crowd being more matured I havent read too contradicting statements.

Surprising to see incorrect fluid error. OP keep us posted with results. I hope dealer didnt mess it up. Which dealer do u use in Boston area?


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## serge1 (Jan 6, 2012)

On the X5 forum, X5d folks determined the DEF incorrect fluid message was due to DEF sensor having been covered by crusted DEF.


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## GreekboyD (Jan 25, 2012)

Did you get it serviced at the dealer after the first warning or fill it yourself? My passive tank has been clogged for well over a year so I just fill my active tank for now until I find the time or care enough to fix this under warranty.


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## serge1 (Jan 6, 2012)

The thread is pretty old. The OP obviously did not bother to come back and post the solution, as often happens on this forum.

My reply was to at least put a closure, in case someone was looking for solution to the same problem. Sorry to resurrect this thread ))


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## Flyingman (Sep 13, 2009)

If you ever let DEF get exposed to air, it crystallizes pretty darn quick. I spilled some overfilling my DEF tank on my MB GL350. It was crystallized on the floor of my garage in a few minutes.


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## lpcapital (Mar 1, 2007)

serge1 said:


> On the X5 forum, X5d folks determined the DEF incorrect fluid message was due to DEF sensor having been covered by crusted DEF.


"determined" is a strong word in general, even more in the context of an online forum, and certainly abused when associated with a not-better-defined "DEF sensor". In other words, what are you talking about? There's no "DEF sensor": DEF quality diagnosis (particularly in respect to dilution) is done by the pre and post SCR NOx sensors that never come in contact with liquid DEF. Are you talking about crystallized DEF on the metering valve? Let's not just use generic and incorrect terms...


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## F32Fleet (Jul 14, 2010)

I wonder if a bad NOx sensor was to blame?


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## Flyingman (Sep 13, 2009)

lpcapital said:


> "determined" is a strong word in general, even more in the context of an online forum, and certainly abused when associated with a not-better-defined "DEF sensor". In other words, what are you talking about? There's no "DEF sensor": DEF quality diagnosis (particularly in respect to dilution) is done by the pre and post SCR NOx sensors that never come in contact with liquid DEF. Are you talking about crystallized DEF on the metering valve? Let's not just use generic and incorrect terms...


I thought they had some sort of sensor in the tank that could detect improper DEF Fluid? Perhaps based on density, conductivity, etc...?:dunno:


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## Flyingman (Sep 13, 2009)

Flyingman said:


> I thought they had some sort of sensor in the tank that could detect improper DEF Fluid? Perhaps based on density, conductivity, etc...?:dunno:


Attached is an interesting EPA article about the subject of DEF dilution. Seems they anticipated the general public may be tempted to substitute alternative (cheaper) liquids! Always looking out for us.

NOx sensor appears to be the method used so far but actual in tank sensors are under development.

Good to know.


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## Axel61 (Mar 10, 2011)

I had the DEF sensor CRUD the exhaust area of the urea and it brought me an SES, they cleaned it but it damaged the forward and aft NOX sensors


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## 335dFan (Nov 8, 2012)

There is an older PDF file named "Technical Training - Product Information: Advanced Diesel with BluePerformance" that was posted on one of the two forums many months ago. I am on the road with only my iPad so can't repost it. But from page 60 on it has a nice discussion under the heading "Overview of Selective Catalytic Reduction." Grossly simplifying the explanation because of soft keyboard, it discusses two sensors that both measure nitrogen oxides in the exhaust gases, and from those measurements determines how much DEF to inject (sensor before the SCR catalytic converter) AND whether the reduction is succeeding (sensor after the SCR catalytic converter). Algorithmic calculations using these measurements and before-after comparisons influence the injection rates, failure conditions, and even whether the incorrect fluid is being used. Sorry for this for those who already know all this and/or for where I have erred. 


Sent from BimmerApp mobile app


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## lpcapital (Mar 1, 2007)

335dFan said:


> There is an older PDF file named "Technical Training - Product Information: Advanced Diesel with BluePerformance" that was posted on one of the two forums many months ago. I am on the road with only my iPad so can't repost it. But from page 60 on it has a nice discussion under the heading "Overview of Selective Catalytic Reduction." Grossly simplifying the explanation because of soft keyboard, it discusses two sensors that both measure nitrogen oxides in the exhaust gases, and from those measurements determines how much DEF to inject (sensor before the SCR catalytic converter) AND whether the reduction is succeeding (sensor after the SCR catalytic converter). Algorithmic calculations using these measurements and before-after comparisons influence the injection rates, failure conditions, and even whether the incorrect fluid is being used. Sorry for this for those who already know all this and/or for where I have erred.


Yes. Thanks for clarifying: that is the same thing I know. There's no "DEF sensor that cruds up"... It may be crystallized DEF on the metering valve, but that is no sensor, it's just a valve.


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## FredoinSF (Nov 29, 2009)

Here's the doc referred to above ^^^


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## 335dFan (Nov 8, 2012)

There is much more in the discussion text that is useful, such as how the system decides when to transfer from the passive to active reservoir and how much it does at one go. It goes a long way in describing some of the things we experience in the use and refilling of DEF. 


Sent from BimmerApp mobile app


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## Nulevel (Sep 3, 2015)

Flyingman said:


> I thought they had some sort of sensor in the tank that could detect improper DEF Fluid? Perhaps based on density, conductivity, etc...?:dunno:


Apparently it does have sensors. My owner's manual conveys steps to take if filling DEP with "incorrect fluids."


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## lpcapital (Mar 1, 2007)

Nulevel said:


> Apparently it does have sensors. My owner's manual conveys steps to take if filling DEP with "incorrect fluids."


No it doesn't. There is absolutely NO SENSOR that DIRECTLY measure the quality of the DEF in the tank.

The quality is assessed using the NOx sensors. If the DDE sees a sudden change in the NOx sensor response upon changes of the metering valve duty cycle calls is "Incorrect DEF". Because of the this an "Incorrect DEF" message could be either really incorrect DEF (unlike, unless you brew your own) or either a clogged metering valve or bad NOX sensors.


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## Doug Huffman (Apr 25, 2015)

I doubt DEF crystallizes under conditions found IN the system. IIRC more than a kilogram of urea will dissolve in a kilogram - liter of water.


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## Nulevel (Sep 3, 2015)

So if you get the DEF warning light (999 miles to shutdown) before the regularly scheduled maintenance, is it "covered" under CPO extended warranty?

i.e. will the dealership re-fill DEF at no charge?


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## FredoinSF (Nov 29, 2009)

Nulevel said:


> So if you get the DEF warning light (999 miles to shutdown) before the regularly scheduled maintenance, is it "covered" under CPO extended warranty?
> 
> i.e. will the dealership re-fill DEF at no charge?


No, DEF refill is not covered by CPO warranty. CPO is warranty that covers mechanical defects. It does not cover maintenance nor consumables such as DEF. 
BMW does offer separate coverage for maintenance past 4/50 and it is possible you have it, but it is not referred to as CPO.


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## Nulevel (Sep 3, 2015)

FredoinSF said:


> No, DEF refill is not covered by CPO warranty. CPO is warranty that covers mechanical defects. It does not cover maintenance nor consumables such as DEF.
> BMW does offer separate coverage for maintenance past 4/50 and it is possible you have it, but it is not referred to as CPO.


OK thanks but let me ask this (and I'm not picking on you...but I do want to understand):

Why am I responsible for paying for the DEF refill on a CPO vehicle? Wasn't this supposed to be done on the last oil change?

I personally feel like it's their fault, not mine.

Any other opinions/experiences on this is appreciated.

I hate to go into the dealership screaming but if they try to charge me one fvucking penny then I'm gonna be p1ssed.


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## Master_Chase (Jun 8, 2015)

Nulevel said:


> OK thanks but let me ask this (and I'm not picking on you...but I do want to understand):
> 
> Why am I responsible for paying for the DEF refill on a CPO vehicle? Wasn't this supposed to be done on the last oil change?
> 
> ...


Was DEF included in the bill?


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## 335dFan (Nov 8, 2012)

DEF is a maintenance item, not a warranty item. Same as an oil change. Having said that, mine is not a CPO. I'm at 53k miles, on an extended warranty until 84 months/100k miles.


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## Nulevel (Sep 3, 2015)

Brought it in to the dealer today and the first thing I said was, "I don't expect to pay for DEF refill because it should've been filled properly to begin with." 

Service advisor gave me no problems. They're gonna fill the DEF for free--not that I think that they're doing me any favors. Mine is a CPO and I have the extended warranty.


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## KeithS (Dec 30, 2001)

Nulevel said:


> Brought it in to the dealer today and the first thing I said was, "I don't expect to pay for DEF refill because it should've been filled properly to begin with."
> 
> Service advisor gave me no problems. They're gonna fill the DEF for free--not that I think that they're doing me any favors. Mine is a CPO and I have the extended warranty.


Remember the extended warranty does NOT cover DEF fills, just as it doesn't cover oil changes, wiper blades, any filters, etc. DEF is not expensive, around $12 for a 2.5 gallon jug at any auto parts store or truck stop (not the dealer). They even sell it at home depot.


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## bimmerdiesel (Jul 9, 2010)

Nulevel said:


> Brought it in to the dealer today and the first thing I said was, "I don't expect to pay for DEF refill because it should've been filled properly to begin with."
> 
> Service advisor gave me no problems. They're gonna fill the DEF for free--not that I think that they're doing me any favors. Mine is a CPO and I have the extended warranty.


Good dealers usually fill it up. Every Time I went for some warranty work, they have topped off all fluids including DEF. But like other members said it is not covered under warranty or CPO. If it was covered (lets say hypothetically) you would be charged $50 as deductible.


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## Nulevel (Sep 3, 2015)

Thanks guys. 

I had the wipers changed; oil changed; DEF refilled; air intake part (recall) changed.

Paid $0.00. 

I'm not exactly sure which warranty I paid for my X5. I bought it last year, SEPT 2015. Paid $2,000.00 and it's good for one year. 

She's as good as new now.


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## bimmerdiesel (Jul 9, 2010)

Nulevel said:


> Thanks guys.
> 
> I had the wipers changed; oil changed; DEF refilled; air intake part (recall) changed.
> 
> ...


Check if you bought maintenance instead of warranty. If it's warranty and dealer is doing all this then it must be some dealer promotion.


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