52k miles and I now have a code. Is the sensor gone bad or can something else drive this, bad fuel, clogged fuel filter?
Is this sensor really $400 plus tax, that's craziness!! And there are 2!

Thoughts

bump

Our 2013 S350 recently got the same code, P2201, plus P229F. Both indicate a problem with the front NOx sensor. It's still under CPO warranty and the dealer just replaced the sensor. Thank God for the warranty! It is an expensive part.
If not for the warranty, I'd check into trying to clean the sensor.
Car has 43K miles.

I drove to Bulgaria and filled up at some random gas station. A few days later the check engine light came on.
P229F Nox sensor 2 bank 1
P2201 Nox sensor 1 bank 1

Apparently, low-quality fuel will damage your sensors. Both need to be replaced now.

My 2013 only had one sensor that triggered 2 codes

Most of these problems are related to Mercedes and Bosch causing it to begin with.

Mercedes and Bosch are going to lose more the a few billion dollars. They are going to lose their reputation, customer trust and confidence in their product and services.

Mercedes is obligated to modify/fix majority of the BlueTec cars and vans plus 5 years of warranty after the fix.

Here is the link for the settlement information:

Daimler AG and Mercedes-Benz USA, LLC Clean Air Act Civil Settlement | Enforcement | US EPA

Here is the link for class action settlement:

$700 Million Mercedes Diesel Emissions Class-Action Settlement Details Announced | Hagens Berman (hbsslaw.com)

Here is the link for DOJ for the clean air ACT lawsuit:

The U.S. Reaches $1.5 Billion Settlement with Daimler AG Over Emissions Cheating in Mercedes-Benz Diesel Vehicles (justice.gov)

Here is the link for a website that is not populated yet as of 12/12/2020 by Mercedes for providing information and instruction:

https://www.mbbluetecsettlement.com

Hi I just joined the forum, I just have the same issue of NOx sensor failure and DefBlue start remaining 5 took it to the dealer since my ML is 2013 and miles 94000 is out of warranty, the cost MB dealer estimated is from 2,300.00 up to 11,000.00 that is because they mentioned if the sensor does not come out clean they will need to replace the whole system. I called MB USA but waiting for an answer on how they can help sine I have been with MB for several with other cars.
Someone mentioned about the software or something to calibrate the NOx sensor does anybody know the application and where to buy it? I am thinking on changing the sensors by myself

The dealer is just coving their butt worst case because the vehicle is 7yrs old and worried the sensor may not come out of the exhaust pipe. You won’t have an issue if care is taken. Meaning if it won’t budge you just heat the bung with a torch to expand the hole amd the sensor will screw right out. They are $400 online for oem. You will have to resent adaptations in Xentry or a local shop with a high end scan tool should be able to do it too. It’s really simple and about a 2hr job tops. You can have Xentry cloned from China (this is what I did) on a laptop, it was about $800 and shipped 2nd day air.

if you have your own laptop you just replace the hard drive
https://m.obd2tool.com/goods-5064-Me...With+WiFi.html

Mercedes is responsible to change and fix your issues at no cost plus 5 years of warranty after the fix as part of the settlement with EPA. Please read the information from the links I provided. You will also receive money from the class action settlement. Unfortunately it is a matter of waiting if you can for your turn to come up. there are several other parts that need to be changed by Mercedes at no cost plus software update. New Nox sensors that you want to change at your own cost may get damaged because the entire system needs to get fixed.

Here are the links again:

Here is the link for the settlement information:

Daimler AG and Mercedes-Benz USA, LLC Clean Air Act Civil Settlement | Enforcement | US EPA

Here is the link for class action settlement: You have to register when website becomes live.

$700 Million Mercedes Diesel Emissions Class-Action Settlement Details Announced | Hagens Berman (hbsslaw.com)

Here is the link for DOJ for the clean air ACT lawsuit:

The U.S. Reaches $1.5 Billion Settlement with Daimler AG Over Emissions Cheating in Mercedes-Benz Diesel Vehicles (justice.gov)

Here is the link for a website that is not populated yet as of 12/12/2020 by Mercedes for providing information and instruction:

https://www.mbbluetecsettlement.com

Here is the District Court’s ruling:

2020-03-25-mercedes-bluetec-opinion.pdf (hbsslaw.com)

Hello guys,
I think this blog can help you identify and fix your issue https://xenons4u.co.uk/blog/p229f62-...des-explained/ because it has a lot of information and also, they explained all error codes in detail, I would be glad if you find it helpful

When your sites quotes 150GBP for the probe, in USA we are having ebay seller having $70 price tag.