Hi Folks,

My GLK 250 has 41,000 miles and just had the NOX sensor go bad... Has anyone else had this issue? What typically causes this?

Thanks,

Ed

 

The search is your friend. You will find that many have had multiple nox sensor replacements as well as differential pressure sensor replacement and DPF replacements. You are getting off light with just one at 41k.

 

I

 

I wonder who has gone the longest without a NOX sensor failure on a 13 or 14 250. 41k is impressive. Took me less than 2k when I owned one.

 

Never a problem here and I'm at that mileage. I suspect some of that may be attributable to the driving style. Supermarket and schlepping the kids wouldn't allow burning off the pollutants while more 'distance' driving would.

 

I bought mine last August with roughly 55k miles on the clock, and there was a check engine on upon purchase, which the dealer agreed to solve, and it was the two sensors. The previous owner did mostly highway driving.

 

I did a search earlier and had found a couple of threads related to this topic. One thread indicated that they recently switched to a new NOX sensor part that should be more long lasting.

I bought this vehicle with 38k so ill assume that it was replaced once earlier and not with the new part number.

I am doing lots of short trips, plus it stinking cold out right now which may have pushed it over the edge...

 

Just someting else to check and keep in mind.....I have seen a few of these concerns on the glk 250. What I have found is exhaust system leak. The DPF has two sealing rings, one on either end of the flanges, those seem to be one point where they leak. I found this cause specifically on one glk 250 that came to me after 2 dpf replacements. multiple nox sensors and dpf sensor and updated dpf harness.

 

I actually traded it back in, but I had almost 50k. Never had any issues with that car other than panoramic roof motor going bad. It saw alot of highway miles though.

 

My dealer just changed 2 NOX sensors today at 62650 Km.(upstream and downsteam sensors) on garanties. I noticed recently a small exhaust smell around the engine compartment when i start in the morning with extreme cold weather (Quebec, Canada). I told that to the dealer a month ago before doing the 60,000 Km maintenance and the said they find nothing special. But after reading what TommiM said...i will take a closer look to that exhaust smell related to NOX sensor and leaks...make sens to me. Leaking exhaust ...less PPM at the sensors. They made a road test after changing the 2 NOX sensors : results, Upsteam NOX 110 ppm...Downsteam 25 ppm, seems OK.

 

Those sensors are no doubt covered by the emissions warranty. That lasts for something like 7 or 8 years?

 

I own a 2013 250 glk bluetec in Canada and according to the waranty manuel the nox sensors are waranty 2 years. Where did you get that information?

Also does someone know where I can find that nox sensor on my car? I have the related check engine codes p229f and p2201. I would like to visually inspect the sensor and possibly replave it.

 

Yes, mine got bad around 40kmi. I have moved to Finland and local MB dealer here tested error P24ae00. My general device just says P01/02 and P02/02. What code you had? Did you have the sensor replaced? Didi it help?