[ululi1970]

I recently bought a used 2014 328d. 91k miles. Today, as I was driving on the highway, the CEL came on. My scanner indicates code 26F500 and 26F600.

It is possible that the DEF level is low? The car had the last oil change about 8000 miles, and I was planning to change the oil in about 1000 miles, and top off the DEF. However, it is my understanding that a low DEF level would trigger a different light.

I am fairly mechanical competent, though this is the first modern diesel I own.

What brand of DEF do you guys recommend? And should I drain the tank (how?) before adding the new one.

For what matters, I live in Phoenix, and it has been hot (100's hot) over the last few weeks.

Any suggestion is welcome. Love the car so far.

[ululi1970]

Poking around, I found this service bulletin
https://static.nhtsa.gov/odi/tsbs/20...49353-9999.pdf

It does describe my situation...

[shiftdnb]

can't really help you much with the codes but people recommend just going to your local VW dealer and picking up some DEF there. Seems to be cheapest.

[ululi1970]

well, to begin I have ordered a ENET cable and will download the ISTA+ software. The service bulletin mentions that, if the DEF is good, the solution is a software fix on the DDE. Will ISTA+ allow me to upgrade the module? Boy, I miss the days when all you need to fix a car was a set of socket wrenches...

[Enabled]

0x26F500 DeNOx system, efficiency: efficiency too low in range 1
0x26F600 DeNOx system, efficiency: efficiency too low in range 2

This is really 1 of 3 scenarios here:

1. Software update needed (not as likely)
2. DEF fluid quality is low (possible, correlate with when you last filled it and determine if it's your fluid. Solution, drain some and fill with some good quality DEF)
3. NOx sensor/s are dying (very possible, take it to the dealer as your NOx sensors have 10yr 120k mile extended warranty)


It's worth noting that if there's a TSB, you're better off taking it to the dealer to solve.
Also, dealer will replace your NOx sensors for free if the fluid is fine.

Many/most of the 328d I have seen are up to date on the DDE software, however it's worth checking.

I do not recommend updating anything on your own just yet, especially if you're not familiar with the software. The ISTA+ you are downloading is pirated, so anything can happen. ISTA does not allow you to update just 1 module, it will attempt to update everything (24+ modules in the car), which can cause some failures in other modules. I'd leave this for more experienced users. I've been asked so many times to help recover cars from failed flashes, more than I could count.

[ululi1970]

Thanks Enabled .
The car was regularly maintained by BMW dealers, but I did not see any record that the NOx sensors were replaced.

I have no idea when was the last time the DEF fluid was refilled. I presume when the last oil change was performed, which was last year, about 8,000 miles ago. The car likely sat on the dealer lot for a couple of months (April and May), and of course it is Arizona, so daytime temperatures have been above 80F for a while now (it is 105F right now).

My plan of action is to test the existing DEF fluid with a refractometer, and replace it with some fresh one if out of spec. Can just siphon off the existing fluid from the filler cap or must it be drained from the bottom? (and yes, I am not going to suck it up with a hose in my mouth ) Any recommendation on where to get DEF?
I will then clear the codes and drive it. If the codes return I will contact the dealer. I still have several months before the warranty expires.

[Onizukachan]

I always used blue def from local parts store, however, one specific parts store that I knew had good turnover on stock. Or the Walmart that I knew did.


Other stores you’d walk in and there would be dust on the box, indicating it had been sitting a while.

The stuff does expire, settle out, whatever it is that it does, so you may be onto something there. AFAIR there is no bottom drain, so you’d be siphoning it out the fill port.

[ululi1970]

I was able to pull a few drops of DEF from the tank, and the refractometer shows that it is smack where it is supposed to be.

I will try to schedule an appointment with the dealer. In the meanwhile, is it safe to drive the car? I was planning to drive to Tucson this weekend (about 250 miles round trip) and I do not want to get stuck in the middle of the desert...

In the issue of ISTA+, I found this place that sells a copy of the software https://www.bimmerdiagnostics.com/#x...Anchor:58AHNEc
It this a pirated copy too?

[Enabled]

They're all pirated, so it's even worse to pay someone else for something they got for free online. That doesn't mean they don't work, but know that support will be non-existent.

The only place that offers it officially is https://aos.bmwgroup.com/web/oss/start

That being said, there are more users of the downloaded versions than the official. It works fine.

The official one bricks cars too just as well sometimes
If you want to update just 1 module, without touching anything else, it's better to use esys (BMW engineering flashing and coding software), but it's also a bit harder to use.


Do you have a countdown to no start currently? The car is safe to drive.
If you have an ENET cable and a windows laptop available, I may be able to help with some things remotely without any software on your end.

[ululi1970]

Thank you Enabled !
There is no countdown as of yet, and I have ordered a ENET cable, will be here mid july, but I will be out of town. I'll PM you when I am back.

[ululi1970]

What do you know. Yesterday, on my way to Tucson, I stopped before hitting the highway to pick up something at Home Depot. When I restarted the car, the CEL light was off and stayed off for the rest of the trip. I will scan again when I am back home.

On one hand I am happy, but if the problem is indeed with the NOx sensors going into the sunset, I'd rather have them fail when still under the extended warranty.

[ululi1970]

Things are getting weirder. I drove back home, and still the CEL stayed off. However, the same scanner that I used to get the codes out of the DDE module now does not see the DDE. There is still a P207F and a P20EE pending codes in the OBDII.

[Enabled]

That's odd, probably a glitch with the scanner. You being able to get codes out of OBD2 section means that the DDE is communicating fine with your scanner.

[ululi1970]

I rescanned tonight and the DDE shows up. The codes are still there, though the CEL is still off. I will drive 90 miles tomorrow, then will have to let the car sit for a month while I am overseas.

[Enabled]

The CEL only comes on in certain conditions, it has nothing to do with presence of codes.

[ululi1970]

At the latest scan, the OBDII has no pending, active or permanent codes (before it had a permanent P207F and a P20EE). If I understand OBDII permanent codes, it means that during the driving done in the last few days the DDE has determined that the fault has been resolved and has deleted them. Interesting enough, the codes are still there if I read them from the DDE instead of the OBDII.

[Enabled]

Yes, most codes have healing counters, but it's not necessarily deleting. They will stay in memory when read with a good tool.

OBDII code reporting is a lot more primitive than the BMW manufacturer code reporting system in this case. There are situations where there are 6-8 very specific and detailed manufacturer codes assigned to one OBDII code, because the OBDII codes aren't detailed enough.
OBDII is an emissions compliance system firstly.

[ululi1970]

Took it to the dealer today. Just received an email indicating I need a new SCR transfer pump for which they are asking $1300. I saw that the pump is about $400. Is replacing the pump something that can be done at home? As I said, I am failry mechanically competent and not afraid to work on cars.

[ululi1970]

No wonder they call them stealerships. The passive tank is located between the right rear wheel and the bumper. The pump is located on the side of the tank facing the bumper. Once located, it took a whole of 5 min to remove it, unplug it and remove the lines. One 8mm nut is all it tkes. There is not even a need to remove covers/heat shields. And the dealer was asking me $630 for labor alone!
Now I am waiting for the replacement part to arrive.

[ululi1970]

While waiting for the pump, I decided to do some more digging. I drained the passive tank, which had about a gallon and a half of DEF. I also decided to drain the active tank, which to my surprise was actually full.
I would have thought that since according to the dealer the transfer pump needed to be replaced, the active tank should have been empty or nearly so. So I rigged a little test setup for the pump, which seems to work just fine.
I then reinstalled the pump, put about about 2 gallons of fresh DEF into the car, reset the codes and went for a drive in the desert. After less than 200 miles, the original codes are back, plus a 26EF00 new code.
At this point, I am thinking that
a) the dealer was trying to pull a fast one on me.
b) I will remove and clean the DEF injector and drive some more.

Any other suggestions? Also, I will try to get the INSTA software even if I have to pay somebody on eBay for the link. I tries several torrent download links that I found online but none worked. $25 seems a reasonable price, considering that the stealership charged me $250 with nothing to show for it.

[ululi1970]

I finally got ISTA+ istalled.
I had a code relating to the transfer pump, but according to ISTA it does not trigger a OBDII code. At any rate, I swapped the transfer pump just in case. Since the active tank is full, I cannot test it until the level drops down a bit.
I also removed the DEF injector, and gave it a good cleanup.

I ran a complete test of the SCR system this weekend. For the record, itis divided in three parts: the SCR passive tank (levels and pressurization of the feed line), the injector (spray pattern and delivery) and then the SCR system proper (this one lasts 50 minutes, runs the engine at different RPMs ,... pretty fun to watch)
The verdict is a bad temperature sensor upstream of the SCR converter.

As far as the dealer suggestion, yes there was a code related to the pump, but that code does not trigger a OBDII code. In fact, as long as there is DEF in the primary tank nothing in the actual operation of the SCR system depends on it.

Based on what I have read online, the temperature sensor upstream of the SCR converter is used by the SCR module to optimize the amount of DEF injected into the stream. With erratic values, I guess the SCR defaults to some default value based on load/rmp, thereby reducing the efficiency of the system.

I have ordered a new sensor (it is not expensive). Should be relatively easy to swap.

[ululi1970]

Replacing the EGT sensor did not cure the problem. Rerunning the SCR test, it said that the Nox sensors were bad. So I went to a different dealer in town, who confirmed it and will have them replaced under warranty.

Bottom line, it was as Enabled said. And I am glad that I followed his advice (and my instinct) not agreeing to have the other stealership replace the transfer pump. That would have been $1300 down the drain.

On the plus side, I was given a 2023 228i as a loaner and it is quite fun to drive. I may actually drive it up tomorrow to the Colorado Plateau if they can't fix it by then (and at this point, I am hoping they won't )