FIXED: NOX Sensor code @ 145,000... Time for delete?

[crystalworks]

EDIT: Fix was replacing the front NOX sensor with a used OE part. $49.



Just looking for some guidance from the "been there, done that" diesel owners. I am getting a code for a NOX sensor (haven't looked into which one as both would be replaced if I go that route).

I recently had the thermostat replaced (I had recently had back surgery) after my wife and I replaced the glow plugs and their module. Now, the NOX sensor code presents a new decision as the parts are +$1000 for new OES sensors. After reading a bunch on deletion I was leaning that way and had the approval of the wife unit as well... but ran across the suggestion that the duramax NOX sensors may be the same units as BMW's. I am tempted to order a couple of those just for testing purposes.

If I can get out of the repair for the cost of the duramax sensors then I think I'll call it a day as they are SIGNIFICANTLY less expensive. As a bonus it would do the community a huge service to find out if they in fact are serviceable replacements for BMW's sensors. What do those who have deleted think? Is it worth the time/effort and relatively low cost of the experiment vs. the $2000 delete but never having to worry about the expensive diesel related systems again.

I know nobody can answer the above question for me... but wanted the thoughts of those who have come before and have vastly more experience with these than I. Appreciate your feedback.

[DSE70]

I'm wrapping up my delete this weekend, the system is installed but I found a couple of maintenance items to resolve while everything is apart.

I have about 24 hours of work into it, granted I did it solo. That includes egr/swirl flaps/ thermostat. I don't think it's bad considering two estimates I had were for 20 hours of labor to install. All-in I'm right around $2k in parts and that was buying them on sale. If you take it to a shop I would expect $4-4500.

I'm the type of person who would rather tinker in the garage than go out drinking, so the time invested was rewarding for me. I also have a spare vehicle to drive. The work was fairly physical so I wouldn't recommend it on a bad back.

That being said, I'm excited to drive it and get back to the Dyno. If I wouldn't have done the work myself I probably wouldn't have done the mod just because I am cheap and this doesn't add value to an ever depreciating vehicle.

In your case, if you want to delete it - now is the time. If you're not sure... Then it's probably not worth the work. If you need nox sensors there are plenty of oem ones used. In fact at least one of mine has less than 15k run time on it. They are pretty simple to get to. Pm me if you want to make an offer or check out ebay for used ones. That would be my recommendation for anyone who isn't in a "hell yeah" state of mind about taking on a delete.

Sent from my XT1650 using Tapatalk

[seattle]

There's strong evidence the NoX sensors are a wear item, designed to last under 50K miles. If I was in your situation, I would just get a few used ones for cheap, as also recommended by DSE70. They can be had for a little more than price of shipping.

You would need to calibrate them using Rheingold.

[crystalworks]

Thanks for your input fellas. The used price is the same for those duramax diesel NOX sensors. I am also a tinkerer (shadetree) and am curious as to the results trying one. I may order a used OE BMW one and a used duramax one just to check it out.

If those don't pan out then a delete does sound tempting. With the mileage on the truck, I am sure much of the clean diesel tech stuff is going to go out sooner rather than later. The EGR valve and cooler, thermostat, glow plugs and module have been done... but I worry more about the other more expensive components.

The back is doing much better after surgery last November, though I did have a disc re-herniate it is not as bad as the first time and does not generate as much pain. I will definitely be doing the delete myself if we go that route.

[seattle]

I recall user ZetaTre/lpcapital attempted to retrofit duramax NoX sensors and it didn't go anywhere. Search this and bimmerfest.
I still think your best route is getting a used NoX sensor for under 100$.
Also, despite mine being deleted, I'd recommend you prolong keeping your emissions components until the cost is close to $2,000. That's about what will cost to delete and tune. There are some drawbacks of going deleted.

P.S. Join "North American BMW Diesel Owners" group on Facebook. Plenty of expert advise there, too, especially related to tuning. Folks sell their removed emissions stuff there for pennies on dollar.

[ZetaTre]

Originally Posted by seattle

I recall user ZetaTre/lpcapital attempted to retrofit duramax NoX sensors and it didn't go anywhere. Search this and bimmerfest.

Yes, I looked into it when one of my NOX sensor was acting up but never spent too much time on it since it was replaced under warranty. If it fails again I'll go to the local GM dealer and take a look.

Cummins/Ram and Duramax/GM both use Continental NOX sensors, now the question is which one has a long enough wire and which one has a connector that works with BMW. The NOX sensor cannot be separated from the control box.

It's hard fro pictures to really see if the connector is the same or not, but they should all have 4 pins: CAN+ CAN- Ground and 12V...

[crystalworks]

Originally Posted by ZetaTre

Yes, I looked into it when one of my NOX sensor was acting up but never spent too much time on it since it was replaced under warranty. If it fails again I'll go to the local GM dealer and take a look.

Cummins/Ram and Duramax/GM both use Continental NOX sensors, now the question is which one has a long enough wire and which one has a connector that works with BMW. The NOX sensor cannot be separated from the control box.

It's hard fro pictures to really see if the connector is the same or not, but they should all have 4 pins: CAN+ CAN- Ground and 12V...

Both of these were 5 pin on the controller to body side. I got resistance on pins 3 & 4. Was the same on both the old and the "new" sensor. The sensor itself had 7 wires going to the control box.

[ZetaTre]

Originally Posted by crystalworks

Both of these were 5 pin on the controller to body side. I got resistance on pins 3 & 4. Was the same on both the old and the "new" sensor. The sensor itself had 7 wires going to the control box.

That's very possible that I got the pin count wrong, I was going off of memory.

In any case, I believe it's very very unlike that the controller is what goes bad. My suspicion is that is the actual catalyst element inside the probe that gets poisoned. The NOX sensor effectively works like a wideband O2 sensor with an added step. There's a catalyst inside the probe that takes NO and NO2 and brakes it down into N2 and O2. The sensor then measures the amount of O2 and calculate NOX. All the processing is done in the controller box that sends back to the DDE a processed signal via CANBUS. The DDE doesn't get a raw analog signal from the sensor, but a processed value from the controller.

It's my understanding that there's a baseline calibration done on each individual sensor that is uniquely paired to a controller. I think that's why they are not sold separately.

I'm not really sure there's a way to assess whether a sensor is "good" or "bad" without a known sample to test the reading against.

[crystalworks]

Originally Posted by ZetaTre

I'm not really sure there's a way to assess whether a sensor is "good" or "bad" without a known sample to test the reading against.

I'm not sure there is either... at least not without expensive test equipment. I just ohm'd the pins for s's and g's really to see if there would be any differences between to two units.


It's a complex setup for sure. The only real test I am concerned with is whether or not the NOX codes and SES light come back on.

[crystalworks]

^Thanks again. Will do that then. The allure of the extra power and MPG was definitely a factor but if I can get out of the repair for a couple of hundred bucks... it's a no brainer to keep the system. The child in me wanted to come out and play. Plus the wife gave her support sooooooo.... Makes it hard to thing responsibly.

Can't join the group though as I don't use Facebook. The wife and I got off about 6 years ago. And I think they still have a "real name" policy in place so can't create a dummy account.