2016 S212 E220 Nox Sensor failure @ 75k

[Ricalnic]

So my EML is illuminated, on checking with my Learn OBD reader I can see that the Nox Sensor has failed, “heater fault”
If I reset it I get about 120 miles or so before it comes back.
Car was only dealer serviced for initial 3 years
I have many questions
This appears common looking at this forum
Do Mercedes recognise this as an issue ? Should I approach them first
What is the replacement part no. ?
Any reputable retailers to procure from ? Quite happy to replace myself as have access to a ramp, does this part need to be coded in ?
Thanks

 

[TC350]

So my EML is illuminated, on checking with my Learn OBD reader I can see that the Nox Sensor has failed, “heater fault”
If I reset it I get about 120 miles or so before it comes back.
Car was only dealer serviced for initial 3 years
I have many questions
This appears common looking at this forum
Do Mercedes recognise this as an issue ? Should I approach them first
What is the replacement part no. ?
Any reputable retailers to procure from ? Quite happy to replace myself as have access to a ramp, does this part need to be coded in ?
Thanks

I’m one of the very many who have been plagued by this issue. I’ve had the NOx sensors replaced twice by Mercedes, the first time under warranty and the second time with a £1,000 contribution from them. That last time was over five years ago.

Since then, roughly every year I’ve cancelled the code two or three times over a short period, then it doesn’t appear again for a year or more.

I suspect that the real issue is that the sensor gets a bit clogged up during short trips, leading the software to incorrectly believe that it’s faulty because the readings returned are slightly out of a tight specification. A good blast down the road with a hot engine may be what clears it.

A total of less than ten minutes cancelling codes with an OBD reader is both a lot cheaper and a lot easier than getting MB to sort things out. The “fault” doesn’t do any harm to the engine so nothing to worry about while it’s there.

 

[Ricalnic]

I’m one of the very many who have been plagued by this issue. I’ve had the NOx sensors replaced twice by Mercedes, the first time under warranty and the second time with a £1,000 contribution from them. That last time was over five years ago.

Since then, roughly every year I’ve cancelled the code two or three times over a short period, then it doesn’t appear again for a year or more.

I suspect that the real issue is that the sensor gets a bit clogged up during short trips, leading the software to incorrectly believe that it’s faulty because the readings returned are slightly out of a tight specification. A good blast down the road with a hot engine may be what clears it.

A total of less than ten minutes cancelling codes with an OBD reader is both a lot cheaper and a lot easier than getting MB to sort things out. The “fault” doesn’t do any harm to the engine so nothing to worry about while it’s there.

Hi, thanks for taking time to reply, and I guess that’s much of the opinion I’ve had with the issue.
It’s been interesting the last couple of weeks where the EML illumination has actually went off a couple of times during a run.
I might try a long ‘hot’ run as you say, as it’s one of the things I’ve never actually given the car in all its years, always in eco mode and never thrashed.
Thanks
I’ll report back