NOx - Understanding How Many Of Us

[merc estate]

Keep us updated. we feel your pain and read with interest, good luck.

 

[RobertoMercini]

Keep us updated. we feel your pain and read with interest, good luck.

AdBlue tank replacement unfortunately for me. 1570 cost negotiated down to 1370. Still a massive bill so wondering whether I’ll have any more luck negotiating with customer services given the car is only just 4 years old and 50k miles in. FMBSH too. Even if I can get it closer to 1000/1100 it would make it less of a kick in the spuds 6 weeks before Christmas

 

[merc estate]

AdBlue tank replacement unfortunately for me. 1570 cost negotiated down to 1370. Still a massive bill so wondering whether I’ll have any more luck negotiating with customer services given the car is only just 4 years old and 50k miles in. FMBSH too. Even if I can get it closer to 1000/1100 it would make it less of a kick in the spuds 6 weeks before Christmas

So out of interested, when was the last time adblue was added? and did the car say adblue at that time? or on a service? lastly was the adblue tank drained on a service and refiled? as i wonder if this is all caused by crystallisation.
Sorry for all the questions but maybe i am looking into this more than MB, thanks.

 

[RobertoMercini]

So out of interested, when was the last time adblue was added? and did the car say adblue at that time? or on a service? lastly was the adblue tank drained on a service and refiled? as i wonder if this is all caused by crystallisation.
Sorry for all the questions but maybe i am looking into this more than MB, thanks.

AdBlue would’ve been added at the last service approx 10k miles ago. Don’t know about draining and refilling for crystallisation as it’s not something MB do as part of a service to my knowledge. There’s a lot of unknowns around the tank stuff which is probably why people like me are getting stung for 1400 quid

 

[merc estate]

AdBlue would’ve been added at the last service approx 10k miles ago. Don’t know about draining and refilling for crystallisation as it’s not something MB do as part of a service to my knowledge. There’s a lot of unknowns around the tank stuff which is probably why people like me are getting stung for 1400 quid

Yea they are good at taking your money. I did read on somthing on a B service they are supposed to drain adblue tank and refill. So that was my thinking. But hey they are not bothered another few quid for them.

 

[Moviestar]

Hi Just purchased a ML350 from a privet dealer and only done about 25 miles when the yellow warning light came on giving a P2201 error code so also will have to try and get them to change the NoxSensor. It had the software up date in 2018 so wonder if its the software update is effecting all the cars?

 

[T5R+]

There is an ongoing debate over whether these fixes are warranted for 12 or 24 months - as a few cars have had to return for the same/similar fix.

That is bad luck for the private dealer - thick end of a £1500 repair, if self funded.

 

[N31L]

Hi all I had the same problem for my 2015 ML250 BLUETEC, bought privately had it for 12 months EML came on. Plugged it in with my cheap scanner had the P0426A and P229F codes. Went into Mercedes had the update but NOx Not changed as they said not required and there on back order. A few hundred miles later the EML back on P0426A no NOx code this time. Can I replace the Catalytic temperature sensor on my own or does it need coding, Will I have to take it back to Mercedes? I have just bought the Icarsoft MB3.0 as its far better than my cheap reader would clearing the fault and fitting a new sensor work or is it just the NOX sensor and this a decoy? If its repaired under warranty not an issue but don't fancy a ridiculous bill .....

 

[MancRick101]

I had this 12 months ago with my previous car (W212 - OM651). Went in for MoT and the dealership (Stockport) treated me appallingly. Went to collect the car after MOT and was rushedly given the keys and told “we’ve done the mot and the Nox sensor”. My response was a puzzled “what nox sensor”? His reply (patronisingly) “erm, your engine management light was on when it came in and it was the Nox sensor so we changed it”

I know for a fact that there were no EML lights / warnings when I took the car in. I told the person this and he argued telling me “no, it was definitely on when you brought the car in”.

I was absolutely furious. Blatant hard faced lies. The car had only been bought 4 months earlier from a different Mb dealership.

It is only when I posted online about my shocking experience that I was alerted to this being a widespread issue.

Fortunately I didn’t have any warnings after the fitting of the new Nox sensor, although the car was stolen 4 months later so who knows.

 

[grober]

I believe early Adblue tanks employed twin electrodes or afloat system as level sensors but more recent models use an ultrasonic detector embedded the base of the tank. This senses liquid level by a reflection of the ultrasonic beam from the surface of the liquid back to the detector. While this is possibly less liable to crystallisation problems any fault may involve replacing the entire tank/detector assembly. Here's what's involved in a BMW adblue tank removal-I doubt the Mercedes is any simpler!

 

[Fenman666]

Well just changed nox sensor 2 cleared faults and had a few stop starts and the management light is staying off £124 from fleabay so worth a punt. I will keep you posted

 

[MSG2004]

I bought a brand new 250d gle in 2016.
The car had covered about 12k miles in 2019 had third service via main dealer MB - all servicing was and is main dealer MB.
2019 thrid year service completed - few days after EML on
Adblue messages came up if I recall rightly.
Rang MB those serviced it as adblue added
MB mobile came out spend three hours trying to fix "software problem" but
had problems linking to live MB site.
Car not in limp mode but hesitating
Took car back to those that last service the car and car was a couple of months outside warranty - once careful driver FSH via MB
They told me Nox sensor and software problem.
The persons dealing with us were helpful.
I told them re my concerns that car is practially brand new driven carefully etc and had read re ad blue/nox probs.
Main dealer contact MB, HQ
Main dealer fixed FoC
I thanked them but this is shit re nox/adblue

Last year fool me was misinformed by another MB dealer over the phone saying I had to get emmisosns recall fixed next service I
did - car is less mpg and felt slower for a few months and still lower on mpg.

Mercedes are not what they used to be 30 years ago as dad's 1983 E class was built like a tank - he had it from alsmot new and still had the car when he passed away in 2000 - everything was link a tank but it was so smooth and reliable unlike the diesels these days

Btw, this is the first diesel car for me as I could not afford (well more like justify the 90k+ price) the brand new petrol version of the GLE in 2016.

 

[T5R+]

Last year fool me was misinformed by another MB dealer over the phone saying I had to get emmisosns recall fixed next service I
did - car is less mpg and felt slower for a few months and still lower on mpg.

Many owners say no difference. I certainly am not in that camp and have seen inferior MPG plus in the cold my car holds lower gear even at a steady 60mph unless manually upshift.

Sorry to hear that the pleasure of your car has been dulled by this experience.

 

[MSG2004]

Many owners say no difference. I certainly am not in that camp and have seen inferior MPG plus in the cold my car holds lower gear even at a steady 60mph unless manually upshift.

Sorry to hear that the pleasure of your car has been dulled by this experience.

Thank you for your kind words.

 

[Fenman666]

Still going no faults ….. so cheap alternative seems to have worked

 

[Gspaddock]

I’ll chip in with my Adblue issues.

Bought the car end of Nov 2021 GLC 220. It’s been a frustrating 5/6 weeks of ownership.

Anyway, before Xmas Adblue came on ‘cannot read fluid level’ 500 mile countdown. Took it to dealer, they had it for 2 hrs, flushed out the system? And replaced a part, I’m not sure what, don’t think it was Nox. Light off and away I went with away the tank reading 7000 mile.


A week later the same thing happens again, this time I take it to another dealer closer to home. They initially were kinda refusing saying I should take it to where I bought it from but that’s an hour away. They said it might be nox but 5/6 week wait list. Anyway they done some updates and cleared it. They said the car needs a number of other updates (I’m not sure what) and it’s back in Feb for these.

The tank level had sat at 7000 miles for 5 days now. Should it be decreasing or should I expect the dreaded light again?

In light out the issues I’ve been having I received £300 compensation from the dealer today which I suppose is something towards the heartache I’ve faced since purchasing.

 

[T5R+]

Sounds as if the supplying MB dealer had been very fair with you to date.

NOx sensor replacement is more than 2 hours and so concur that probably not undertaken.

Personally, I would allow the supplying dealer to undertake all corrections and updates.

Interesting to hear over the 7000mile countdown marker - not come across that before. Inclined to keep using car unless lights or other warning comes up.

 

[Gspaddock]

Sounds as if the supplying MB dealer had been very fair with you to date.

NOx sensor replacement is more than 2 hours and so concur that probably not undertaken.

Personally, I would allow the supplying dealer to undertake all corrections and updates.

Interesting to hear over the 7000mile countdown marker - not come across that before. Inclined to keep using car unless lights or other warning comes up.

Yes, they have been pretty good but I wasn’t expecting the car to be back in the garage 3 times in 5 weeks and me without my new purchase for over 11 days in that time.

I just hope these updates etc are not a sticky plaster that is masking the real issue (nox and or tank replacement) and that dreaded Adblue warning is going to reappear soon. Obviously best if it appears in the next 11 months so it can get sorted under warranty otherwise I’ll have a hefty bill on my hands.

The 7000 miles is what it says is remaining before Adblue needs topping up. I was just wondering if this should count down as it’s been on 7000 for close to a week now.

 

[arcton114]

I had this 12 months ago with my previous car (W212 - OM651). Went in for MoT and the dealership (Stockport) treated me appallingly. Went to collect the car after MOT and was rushedly given the keys and told “we’ve done the mot and the Nox sensor”. My response was a puzzled “what nox sensor”? His reply (patronisingly) “erm, your engine management light was on when it came in and it was the Nox sensor so we changed it”

I know for a fact that there were no EML lights / warnings when I took the car in. I told the person this and he argued telling me “no, it was definitely on when you brought the car in”.

I was absolutely furious. Blatant hard faced lies. The car had only been bought 4 months earlier from a different Mb dealership.

It is only when I posted online about my shocking experience that I was alerted to this being a widespread issue.

Fortunately I didn’t have any warnings after the fitting of the new Nox sensor, although the car was stolen 4 months later so who knows.

Just before selling my w205 C250 last year I took it in to MB for a small unrelated job, they kept the car the whole day and on my return at 5pm I was informed the car had had the said Nox sensors replaced due to EML light being illuminated when I dropped it off, all work FOC and was good to go,

I have OCD I know there was no light on, that was a lie in my opinion

I didn’t ask them to do this work and have always declined the diesel gate updates etc, they also brim filled the adblue at the same time,

Don’t really know much about this issue but was a bit annoyed they had done this work without conversation and couldn’t help think something was a bit fishy about the whole affair,

I may be wrong

 

[MoCLK]

Hi everyone,

Thought I'd add to the list. My car is a 2015 E220 which I bought used from a dealer. Had the "refill AdBlue" message come up with the EML.

Filled up and still, the EML light stayed on which indicated an issue with the NOx sensor.

Checked the MB website and the car is due the diesel software update. Will this fix the issue most likely or do the actual NOx sensors need replacing? Don't fancy getting ripped off by the main dealers