Nox Sensor yet again!

[Driventodistraction]

So I have E220d 2015 and in 2019 had two Nox sensors replaced which MB did FOC to my delight. Last week the EML came on again and now it’s a P229F91 Nox sensor 2 cylinder bank 1 that needs replacing. Only two years part warranty and going to cost £749 inc labour and VAT. The lady at Merc told me that if I was only doing short journeys then perhaps I have the wrong car!!! I bought it new in 2015 and it was fine for four years!! Has anyone else had this happen twice and what was the outcome on cost etc.

 

[kianok]

Similar issue here, E220 2016

Car was booked in for service last week and a couple of days before it went in the EML appeared.

Fault is the same as yours and was quoted a similar cost to repair, not that they could have carried out the repair as the part is on back order!

MB have automatically rejected any goodwill despite having full main dealer history.

 

[Driventodistraction]

Absolutely the same! Full service history at main dealer. Got appointment for 7th February to have part fitted, if it’s arrived by then!

 

[Fenman666]

So I have E220d 2015 and in 2019 had two Nox sensors replaced which MB did FOC to my delight. Last week the EML came on again and now it’s a P229F91 Nox sensor 2 cylinder bank 1 that needs replacing. Only two years part warranty and going to cost £749 inc labour and VAT. The lady at Merc told me that if I was only doing short journeys then perhaps I have the wrong car!!! I bought it new in 2015 and it was fine for four years!! Has anyone else had this happen twice and what was the outcome on cost etc.

Had the same problem with mine purchased a nox sensor from fleabay £127 20 minute job to change cleared fault all good

 

[OneForTheRoad]

Had the same problem with mine purchased a nox sensor from fleabay £127 20 minute job to change cleared fault all good

Any link to this on eBay ?

 

[Fenman666]

Just search for this
For Mercedes Benz W172 W222 W221 W251 W212 A0009053403 A0009056900 Nox Sensor. To be fair I think all the merc sensors are probably made in china with various degrees of quality The one I purchased where the wires go into the nox sensor the crimping was not brilliant so I sealed it with silicone to stop any water ingress.
The only thing I noticed was start stop not working but then remembered at service battery was 47% so I purchased a varta replacement one online for £137 fitted it and all is back to normal

 

[Smiley]

I think we can be pretty certain that the sensors are made in China and it seems that they are made to a variable, but generally poor, standard and then sold by MB at a premium quality price. The Chinese suppliers probably can't believe their luck that they can sell a cheap sensor for over £100.

 

[kianok]

Absolutely the same! Full service history at main dealer. Got appointment for 7th February to have part fitted, if it’s arrived by then!

Had a response from MBUK since my earlier post.

£400 fitted is the best they can offer but no idea when!

 

[Driventodistraction]

Had the same problem with mine purchased a nox sensor from fleabay £127 20 minute job to change cleared fault all good

Thanks for the info! Am going to get hubby on to it!

 

[Driventodistraction]

Had a response from MBUK since my earlier post.

£400 fitted is the best they can offer but no idea when!

they really are a nightmare

 

[Fenman666]

they really are a nightmare

Tell me about lol I have been waiting for over a month for a quote to change both. I have chased them up once and was told I am next on the list and they were then going to ring with the quoted wrong name and telephone number!!!!
That is why I did it myself

 

[Supernoodle]

I think we can be pretty certain that the sensors are made in China and it seems that they are made to a variable, but generally poor, standard and then sold by MB at a premium quality price. The Chinese suppliers probably can't believe their luck that they can sell a cheap sensor for over £100.

The MB parts are made by Continental.
The NOx sensors have their own module that communicates with the ECU over CAN. Some enterprising company has no doubt realised they can use some cheap sensor and a module to send some data to ECU to keep it happy. I doubt it actually senses any NOx, as long as it doesn't report any electrical errors errors the buyer will be happy. The ECU might flag some NOx efficiency error later on but that will be after you've used the part, so good luck getting a replacement.

 

[Fenman666]

And good luck getting a replacement from Mercedes’ or even an answer to why your car goes into Mercedes’ dealership with no faults and after their software update and 100 yards travel the light comes on you return they put it on the tester nox sensor mate …… how very convenient!!

 

[Supernoodle]

The Continental and Bosch NOx sensors are pretty much an off the shelf part, but it's down to the manufacturer to implement on the application. They are very sensitive to condensation and easy to soot up.
The fact that the same parts are used by other manufactures without the same number of issues MB have suggest they haven't done their bit quite right.
If the errors start after an ECU update you're right to be suspicious. It sounds like they have started to use the sensor properly now and in conditions they haven't validated or they just weren't reacting to the errors that were already there.
So glad I've got an old jalopy which pre dates the introduction of SCR.

 

[BilalM]

Out of curiosity, those that have had a nox sensor fail what fuel have you been using? I started filling my car with premium diesel once per month and part of me wonders if that is what caused the issue?

On a side note i have joined the class action against MB. Apparently the system update they did did cause parts like the NOX sensor to fail.

 

[Eoseer]

Out of curiosity, those that have had a nox sensor fail what fuel have you been using? I started filling my car with premium diesel once per month and part of me wonders if that is what caused the issue?

On a side note i have joined the class action against MB. Apparently the system update they did did cause parts like the NOX sensor to fail.

where can I join this class action?

 

[BlackC55]

Just search for this
For Mercedes Benz W172 W222 W221 W251 W212 A0009053403 A0009056900 Nox Sensor. To be fair I think all the merc sensors are probably made in china with various degrees of quality The one I purchased where the wires go into the nox sensor the crimping was not brilliant so I sealed it with silicone to stop any water ingress.
The only thing I noticed was start stop not working but then remembered at service battery was 47% so I purchased a varta replacement one online for £137 fitted it and all is back to normal

These are not worth worth using even for a door stop. They will fail very quickly.

 

[BlackC55]

So I have E220d 2015 and in 2019 had two Nox sensors replaced which MB did FOC to my delight. Last week the EML came on again and now it’s a P229F91 Nox sensor 2 cylinder bank 1 that needs replacing. Only two years part warranty and going to cost £749 inc labour and VAT. The lady at Merc told me that if I was only doing short journeys then perhaps I have the wrong car!!! I bought it new in 2015 and it was fine for four years!! Has anyone else had this happen twice and what was the outcome on cost etc.

You probably had the old part numbers fitted. The Nox sensors that went wrong all the time. The later numbers with some software tend to work much better.

 

[Slartibartfast]

These are not worth worth using even for a door stop. They will fail very quickly.

He posted that over 2 years ago. Be interesting to find out if it failed since the.

 

[Speedy55]

Hi Guys,
I had the same P229F91 NOx Sensor 2 (cylinder bank 1) has a malfunction error on my W212 2015 E220cdi
I'm planning to replace it by myself.
But I don't know which one is this. Is it front or rear sensor?
And I don't know the part number to be ordered. Can anyone help me with my questions? I can share my VIN if needed.
Some MB Owners tell that part numbers have changed but compatible with this model. That's why I confused a bit.

Thanks in advance,