Mercedes NOX SENSOR'S (Nox fit for purpose) E220 Bluetec W212 Model Year 2015

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DMST

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Mercedes E220 Bluetec W212
I have a E220 Bluetec W212 NIGHT EDITION 2015.
Full Mercedes service history with 48k, I was away on holiday with the family and engine management light (EML) came on, we were in the sticks as they say and 58 miles to the nearest MB dealership, called MB but they said nothing they can do until the following week as fully booked.

Obviously didn't want to drive it around or back home, took it to a local reputable garage just to see what the problem was and if something serious, they used a Snap on scanner and said it's the nox sensor (sensor 2 bank 1 upstream), also noticed the stop start function was amber on the dash, they replied we aren't MB specialists and think it's probably due to nox / eco system but could be low battery voltage, checked main battery almost 14v showing, aux battery approx. 13.8v, he checked some info and said yep they are fine as 12.4v is the minimum for the system.

He said eco system stop start function is most likely to be related to the nox sensor, no loss of power or acceleration, not sure on fuel consumption as not driven far since the EML.

Engine revs still approx 800 when idle, do I risk driving it ???, hired a car for the week and drove my E220 back home, logged into my Mercedes Me online account and have it booked it for diagnostics, also noticed on my account it shows a MB did a Diesel software update on my car but no date next to it, so don't know when it was done etc, it was serviced by Benz this year in May.

Did some research and yep, the diesel software update relates to nox sensor's !!!.

So clearly MB knows there are problems with their vehicle eco systems / nox sensor's or they would not have created an update, all testing should have been done at the MB factories before selling them to customers, not the way to conduct business.

Further research:

London law firm Fox Williams LLP, in collaboration with US class-action law firm Hagens Berman, is building a group claim in England and Wales that will allege Mercedes deliberately engaged in emissions fraud in the sale of its diesel and BlueTec vehicles by programming an emission defeat device during test conditions which limited illegally high, dangerous levels of Nitrogen Oxide (NOx) emissions normally evident in real-world driving conditions.


I have driven MB cars for 35 years, shocked to hear how this company is now operating, never thought I would consider driving anything else, I will Just have to see what MB say after the diagnostics, will post the outcome and if it's not favorable I will contact London law firm Fox Williams LLP.
 
Last edited:
I have a E220 Bluetec W212 NIGHT EDITION 2015.
Full Mercedes service history with 48k, I was away on holiday with the family and engine management light (EML) came on, we were in the sticks as they say and 58 miles to the nearest MB dealership, called MB but they said nothing they can do until the following week as fully booked.

Obviously didn't want to drive it around or back home, took it to a local reputable garage just to see what the problem was and if something serious, they used a Snap on scanner and said it's the nox sensor (sensor 2 bank 1 upstream), also noticed the stop start function was amber on the dash, they replied we aren't MB specialists and think it's probably due to nox / eco system but could be low battery voltage, checked main battery almost 14v showing, aux battery approx. 13.8v, he checked some info and said yep they are fine as 12.4v is the minimum for the system.

He said eco system stop start function is most likely to be related to the nox sensor, no loss of power or acceleration, not sure on fuel consumption as not driven far since the EML.

Engine revs still approx 800 when idle, do I risk driving it ???, hired a car for the week and drove my E220 back home, logged into my Mercedes Me online account and have it booked it for diagnostics, also noticed on my account it shows a MB did a Diesel software update on my car but no date next to it, so don't know when it was done etc, it was serviced by Benz this year in May.

Did some research and yep, the diesel software update relates to nox sensor's !!!.

So clearly MB knows there are problems with their vehicle eco systems / nox sensor's or they would not have created an update, all testing should have been done at the MB factories before selling them to customers, not the way to conduct business.

Further research:

London law firm Fox Williams LLP, in collaboration with US class-action law firm Hagens Berman, is building a group claim in England and Wales that will allege Mercedes deliberately engaged in emissions fraud in the sale of its diesel and BlueTec vehicles by programming an emission defeat device during test conditions which limited illegally high, dangerous levels of Nitrogen Oxide (NOx) emissions normally evident in real-world driving conditions.


I have driven MB cars for 35 years, shocked to hear how this company is now operating, never thought I would consider driving anything else, I will Just have to see what MB say after the diagnostics, will post the outcome and if it's not favorable I will contact London law firm Fox Williams LLP.

What outcome are you expecting exactly?

They'll diagnose it and will fix it if its under warranty. If its not, good luck unless its got a full MB service history they might give you some kind of goodwill gesture.

These law firms are focusing on the emissions - i.e. what happened to VW in that it was pumping out more Nitrous oxide than they should have been doing. Its nothing to do with the NOX sensor going kaput. I believe something like that will be going on for a few years yet - it won't be easy taking MB to court
 
These law firms are focusing on the emissions - i.e. what happened to VW in that it was pumping out more Nitrous oxide than they should have been doing. Its nothing to do with the NOX sensor going kaput.
The software updates to correct the emissions cheats, are now causing nox sensors to fail. So it's all connected.
 
also noticed the stop start function was amber on the dash, they replied we aren't MB specialists and think it's probably due to nox / eco system but could be low battery voltage, checked main battery almost 14v showing, aux battery approx. 13.8v, he checked some info and said yep they are fine as 12.4v is the minimum for the system.

He said eco system stop start function is most likely to be related to the nox sensor, no loss of power or acceleration, not sure on fuel consumption as not driven far since the EML.
Sounds to me as the batteries were both checked with the engine running, that would give a false reading, they must be checked with the car at rest, either battery will prevent the stop/start working properly if down on voltage, even slightly.
Not sure if the Nox problem would prevent the same issue, just the fact the EML is on would be enough to stop start/stop operation.
 
Not sure why you did not just keep driving it. A sensor has broken....so what - the adblue system is most likely still working as it should it is just that the sensor can not confirm one way or the other so has to assume the adblue system is faulty - but even if it is faulty then it won't do the engine any harm it will just mean that the emissions are out of spec.
Whilst there are lots of problems with adblue systems generally (not just MB), you have an eight year old car that has developed a fault - it just needs to be fixed - your choice MB or an independent specialist. Not sure what that has to do with taking MB to court?
 
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I have a E220 Bluetec W212 NIGHT EDITION 2015.
Full Mercedes service history with 48k, I was away on holiday with the family and engine management light (EML) came on, we were in the sticks as they say and 58 miles to the nearest MB dealership, called MB but they said nothing they can do until the following week as fully booked.

Obviously didn't want to drive it around or back home, took it to a local reputable garage just to see what the problem was and if something serious, they used a Snap on scanner and said it's the nox sensor (sensor 2 bank 1 upstream), also noticed the stop start function was amber on the dash, they replied we aren't MB specialists and think it's probably due to nox / eco system but could be low battery voltage, checked main battery almost 14v showing, aux battery approx. 13.8v, he checked some info and said yep they are fine as 12.4v is the minimum for the system.

He said eco system stop start function is most likely to be related to the nox sensor, no loss of power or acceleration, not sure on fuel consumption as not driven far since the EML.

Engine revs still approx 800 when idle, do I risk driving it ???, hired a car for the week and drove my E220 back home, logged into my Mercedes Me online account and have it booked it for diagnostics, also noticed on my account it shows a MB did a Diesel software update on my car but no date next to it, so don't know when it was done etc, it was serviced by Benz this year in May.

Did some research and yep, the diesel software update relates to nox sensor's !!!.

So clearly MB knows there are problems with their vehicle eco systems / nox sensor's or they would not have created an update, all testing should have been done at the MB factories before selling them to customers, not the way to conduct business.

Further research:

London law firm Fox Williams LLP, in collaboration with US class-action law firm Hagens Berman, is building a group claim in England and Wales that will allege Mercedes deliberately engaged in emissions fraud in the sale of its diesel and BlueTec vehicles by programming an emission defeat device during test conditions which limited illegally high, dangerous levels of Nitrogen Oxide (NOx) emissions normally evident in real-world driving conditions.


I have driven MB cars for 35 years, shocked to hear how this company is now operating, never thought I would consider driving anything else, I will Just have to see what MB say after the diagnostics, will post the outcome and if it's not favorable I will contact London law firm Fox Williams LLP.
This is becoming one of the most reported problems on forums. Do a forum search to see many other owners' experiences. Whilst some owners will not have these problems I wouldn't even consider a Bluetec equipped car.
 
Not sure why you did not just keep driving it. A sensor has broken....so what - the adblue system is most likely still working as it should it is just that the sensor can not confirm one way or the other so has to assume the adblue system is faulty - but even if it is faulty then it won't do the engine any harm it will just mean that the emissions are out of spec.
When I first had the Nox sensor issue, Mercedes gave me a courtesy car even though the sensors were on back order and they could not tell me how long before they could fix my car. They explained that I should not drive it as the engine light is already on and if another fault was to present itself I would never know, because the light is already on.
 

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