DEF Usage?
 

Anyone experienced an increase in DEF usage after the EGR recall/reprogramming?

I am at 32K. My DEF warning never came on between oil changes at 13K and 26K. Both oil changes indicated on the sheet that they refilled the DEF.

That means I went 13K twice with no DEF warning. I just had my DEF warning come on 6K after my most recent oil change?!? That seems like a huge change in usage while my driving habits haven't changed.

I asked my SA to check the Passive tank because a warning this early could mean that the pump was clogged between the passive and active. He said there was nothing to indicate a need to check and that it was completely normal for the DEF to run out after 6K. I asked why I had lasted 13K the two previous times and he basically kept returning to the 'its totally normal" and "I have people come in all the time after that few miles."

I just find it highly unusual that my car would go 13K twice with no warning, and then only go 6K this time. From my perspective, either they lied on my sheet at the last oil change and didn't refill the DEF, or the pump isn't working between the active and passive tanks and the warning came on after the active tank was getting empty and the passive tank wasn't getting pumped over to refill. Is there anything I can do to have them check this pump while still under warranty? I don't want them to push me off for the next 16K miles and then have it fall on me out of warranty.

Ideas? Thanks!

try filling only your passive tank and see what happens

About the 6k mark repeatedly for people has meant one of two things. Either they did not truly fill up both of your tanks even though your paper work says they did OR the transfer mechanism between both tanks is messed up. It of course could mean your car is consuming massive amounts of DEF but I do not think a single person on here has actually had that happen. Be a bigger jerk to the SA, that is what I did when this happened on my car. Chances are they'd never admit to not filling both tanks and you can't prove it either way unless you try to top off both your tanks after they claim to have filled them.

Your SA is BSing you. 6k is NOT normal. Or it might be normal for THEIR dealership because they might not be filling the tanks properly. You are correct to be concerned about it. The manual says that the DEF should not need refilling between services...unless there are certain conditions - like driving in extreme altitudes.

And It's been well documented here that it's usually a problem with under-filling on the previous service or a mechanical problem. I would try to get to the manager.

I don't know if a clogged or failing transfer pump throws a code. But as a courtesy they should check it for you.

Did they top off the tanks for you?

One clue is how much fluid it took to top off BOTH tanks. If the pump is functioning then both tanks should have been empty and it should take 5 - 6 gallons. In that scenario the dealer probably under-filled the tank on the previous service. If it only took a fraction of that amount then I think there is a greater chance of a transfer pump malfunction. Of course that's all on the assumption that they know what they're doing and checking both tanks!

One other question - did your previous service paperwork show the number of DEF units added to the the tanks (Each unit is 2.5 gallons)? On my last two 13k services, the car took 2 units which indicates a "normal" use rate - in spite of the fact that a lot of my driving has been in Santa Fe NM, 7200' above sea level.

Good Luck!

I had a transfer pump problem and it did in fact trigger an SES. But I think some people have had problems with the transfer pump and got no SES. I took the car in because of the SES, not because of getting to the point of low on DEF where as I recall some of the other people took theirs in because of low DEF lights. Now of course this is not to say those others really had no pump issues at all and the dealer simply said they did to cover their initial mistake of not topping off the tanks completely. The cars inability to show some sort of level on these tanks is one of my bigger complaints with the design of things but I am not sure if any car/truck using DEF has a tank level sending unit for such a purpose.

My last two oil changes just have a reference to 'refill DEF'. They didn't list amount used in refill.

I think the failure to have some sort of quantity guage for the tanks really is a design flaw. My situation is a perfect example. They ended up putting two small containers in the active tank to appease me and said they would review at my oil change in 5K. It just really seems like they don't care about really finding out what the problem was, refill error or pump issues. If I could tell how much was left in the passive tank, then I would know immediately which one is the problem. Empty=refill issue Full=pump failure.

I already know they aren't going to take the issue seriously at the oil change. I can tell them straight to their face that they truly are wrong and they just say its normal and there's nothing I can do about it. Maybe I'll have to try another dealer for service as much as I'd rather not:(

I went back in today to talk to my salesman (not my service advisor) and told him I may be ready to upgrade to the 2013 NA M3 just to avoid turbos and DEF:) (My 2007 335i was a buyback) My commute is going from 140 miles a day to 35 a day come November. Maybe this was just good timing:)

I understand that your frustrated with the car BUT the problem isn't with the car - it's with the dealer's service. So my question is why would you buy another car from that dealer? In the scenario you've outlined you're rewarding the dealer for lousy service. The dealership wins on two counts, first they will probably (or at least try to) undervalue your D at trade-in and second reap the benefits of selling another car.

I agree with this 100%, find another dealer and reward them instead. Even let the other dealer know, they will just love knowing some business was lost from one of their "competitors" since all BMW dealers still do compete with one another.

Idea: A)Buy one of those devices made to pump oil out of your crank case through the dip stick tube
B) suck out all of fluid on active side
C) fill up passive side

Start her up and see if DEF light comes on. You might have to be pateinet and give the system a little bit correction time. If DEF light stays on, wouldn't this be grounds for transfer pump indictment?

does the light come on from a active side or passive side sensor?

You have a very good and valid point. Actually, I initially went to my salesman to complain about the situation since he was on vacation when the whole thing went down. He was very clear that next time this happens, or if I have a problem with service on this issue at the time of the oil change, that I should come see him and he will make sure all is right. He agreed that the 6000 miles didn't seem appropriate and that this should be addressed and under warranty.

The conversation continued and he knows I almost bought an M3 when I bought the 335d, but didn't because of my commute. I mentioned my upcoming transfer and we got into the M3 discussion. I was just saying maybe that all this happened for a reason to nudge me in to maybe making a change. Believe me, I'm not going to just blindly upgrade if I got a bad deal. It is already a bad enough financial decision to trade in a car in the second year of ownership, if they tried to fleece me, the deal wouldn't happen. I didn't get to a point of being able to afford an M3 by just throwing money away or rewarding bad service.

No matter what, I'll still have the 335d come the next oil change at my rate of mileage so we'll see how service treats me when the time comes. I won't hesitate to get my sales advisor involved, plus he's probably more likely to come in heavy if there's a potential sale riding on it:)

Interesting point... is there a different warning for the two tanks - active vs passive? I couldn't tell in the tech literature I've read. I know they both have level sensors - but it wasn't clear how they work.

I think you're wise to let this go through to the next service/ oil change. I would get them to properly document the paperwork to show the quantity & type of oil they used as well as the quantity of DEF.

One other consideration... if you are thinking about an M3....I recall reading somewhere that M3s require more maintenance than the everyday 335. If this dealership is falling short on maintaining your D how are they going to do with an M3?

I'm definitely getting things documented next time in. At my rate of driving, 5K miles will come and go in 1-2 months. My rear brakes are telling me I need a change in 1700 miles and my job transfer doesn't come until Nov-Dec, so any potential car change is 4 months out minimum.

Regarding the maintenance, with the new job I should be okay using the dealer for standard maintenance while under warranty for 4 years. The M3 doesn't necessarily require difficult maintenance, just more maintenance, whereas the dealers seem to have no clue regarding these diesel engines. I actually like the idea of having a S65 that I can take to specialists near where I live to work on and do maintenance in between what is covered by BMW's maintenance schedule. I'm stuck with the dealer as my only option for the 335d because none of the shops have much experience with that engine.

We'll see. I look at this as two different issues. I want to get my 335d dealt with and fixed. That will take priority over my next couple visits. After that is dealt with, and if the finances work out on the deal, then I'll get excited about a potential move to an M3.

Your tag indicates that you are in the Bay Area -- there are at least 6 BMW stores right in our area -- go to the next one over and try their service center. All of them are different in their level of expertise and you will find a good one to use. Personally I have had great luck with Stevens Creek BMW service (Erin - formerly with Dinan in Mtn View). Remember a dealership has three profit centers: (1) New Cars - includes the F&I sales (2) Used Cars & (3) Service Center. All are independent of each other and have their own managers. So, your sales person may not have the "juice" to get things done in the service area. I think that even after all this time has passed since the urea tanks appeared, there is still unfamilarity with the system within the service community, and some are more dialed in than others. I would not at all be surprised if your tanks were not actually filled, even though the record indicates they were. If there is a glitch in your car's system now is the time to find it -- not after the warrenty goes away. Good luck!:angel:

@ OP, I've experienced the same thing.

p/s See my post #339 @ http://www.bimmerfest.com/forums/sho...618966&page=14

Great thread folks.My 2011 X5d went 10244 miles before first service and required no DEF
My driving habits have not changed.
At ~17K, my low DEF light went on. My service advisor said to add a small bottle (1/2gal) and that should carry me over till service. I was skeptical but said OK and it was pretty cheap. Now at 18100, my light goes back on???
1. Was I underfilled? Service report at 10244 says I took 1 unit.
2. Transfer pump issue? I suspect #1 is real issue
2. Please explain active v. passive tanks. I see the filler in my X5d on right side and have added fluid there. Where is other filler port?

You were underfilled

Yes I was. At service, just under 6 gallons were added. And my 'add fluid' warning came on a second time right before my service.

The amount added would lead me to believe that I don't have any transfer problems between the active and passive tanks, since both tanks would need to be empty for that much fill to be used. This is a relief, but I still am of the opinion that my DEF usage has increased since the first ECU reflash. It seems to have increased to the point that I no longer can make it without a refill between oil changes.

At least its just having to buy DEF fluid instead of having to deal with a faulty system. Annoyance but not a problem.

Supposedly DEF is metered to inject at some % (1-3%) based on fuel flow measured. This makes sense as it is just a chemical reaction, so many parts per million of DEF to each part of fuel. 1% would be 10,000ppm of DEF?

I suspect your metering is out of whack and is injecting more DEF than it should, so this would be a defect and they should fix it.

Look at it this way, you calculate you may burn 30mpg and you expect 13,000 miles between servicves. 13,000/30 = 433 gallons of Diesel will be burned between services.

The DEF tank holds some 6 1/2gallons, so 6.5/433 = 1.5% of DEF being consumed.

The rate of injection is just too high on your car. They should fix that!

If your getting only 20mpg I would expect you will run out of DEF before you reach 13,000 miles.

Good luck!:thumbup:

No. The ST810 and Intro to diesel tech docs that have been posted here make it clear that they use an active NOx sensor to drive the amount. Remember, there are actually two catalysts: the one in the DPF (which reduces NO--> NO2), and the SCR (which completes the reduction to NOx --> N2 + O2)

Agreed, it is monitored by NOx sensors, but translates to about the same ratio of fuel consumed to DEF used. i.e. you should get about 13,000 miles between refills, but as we have all seen this can vary. It seems easy enough to add some DEF so shouldn't be such a major issue. About same as adding window washer fluid, no?

Q. How can an operator determine how much DEF they will need/use?
A. DEF consumption will be approximately 2% of the diesel fuel consumed. Another way to consider it is that DEF will be consumed on a 50 to 1 ratio with diesel. (For every 50 gallons of diesel fuel burned, you will use 1 gallon of DEF). If you know the average fuel consumption of a vehicle, you can easily calculate the amount of DEF that will be used.
Annual miles for average truck = 50,000 miles
MPG for average truck = 8 mpg
50,000 miles / 8 mpg = 6,250 gallons diesel fuel per year
DEF usage @ 2% of fuel consumption = 125 gallons of DEF / year
125 gallons / 10 gallon tank (average size) = 13 DEF fill-ups / year
Example…..Heavy duty
Annual Miles per VehicleAnnual Total MilesAverage MPG per TruckAverage DEF Tank Size (on vehicle)Annual Fuel Usage (gallons) Consumption per Gallon of fuelEstimated Annual DEF Consumption DEF Fill-Ups per Year 120,000 120,000 6 20 20,000 2% 400 20

Q. Is the DEF dose rate the same for all engine manufacturers?
A. The DEF dose rate will vary slightly amongst engine manufacturers. While most engines will have a dose rate of 2% of diesel fuel consumed, the dose rate will range from 1% to 3%.

Let's see if I got this right:

Annual miles between oil changes = 13,000 miles
MPG for my 335d = 37.5 mpg
13,000 miles / 37.5 mpg = 347 gallons diesel fuel per year
DEF usage @ 2% of fuel consumption = 6.9 gallons of DEF / year
6.9 gallons / 6.1 gallon tank (average size) = >1 DEF fill-ups / year

My first refills were early due to a repeated issue with the transfer pump, but I've made it to the past two 13k oil changes without any DEF adds. I guess BMW's add rate is less. than 2%.

It is 1% to 3%, so can vary. I've made all my intervals except this last one due to mechanic not topping off my DEF. They filled it for no charge, as they should.