NOX sensor stats

[JustmeJB]

I'm in the middle of the NOX sensor issue having just had one replaced costing £700 and now the EML has reappeared so fully expecting it to be the other one despite these being replaced within the last 18 months.

Google NOX sensor issues and the big majority of results relate to Mercedes cars.

So it got me thinking has anyone requested stats from Mercedes as to how many NOX sensors are changed in the UK every year. I wonder if there's a case for these cars being deemed not fit for purpose. I was chatting to my local main dealer today and mentioned a suggestion of hard driving to keep the sensors clean but that contradicts the intention of the ad blue system and also if the car needs two each year costing 1400 then surely that's not right. No surprise he didn't respond verbally but his expression said I hit a nerve.

So just curious if anything like this has been done already and if not then would it be worth it?

 

[C320]

I don’t know much about class action however, I found the post interesting here, where a fellow forum member states in Post No.6 that resetting can sometimes deactivate the code for a year: Nox sensor seized | Parts, Maintenance & Servicing

 

[JustmeJB]

I don’t know much about class action however, I found the post interesting here, where a fellow forum member states in Post No.6 that resetting can sometimes deactivate the code for a year: Nox sensor seized | Parts, Maintenance & Servicing

Funnily enough I was just reading that myself. I'm now trying to figure out what £25 OBD tool the person is on about as it almost sounds too good to be true but definitely worth a go.

 

[C320]

@TC350 what OBD II tool do you use please?

 

[toteimerced]

Maybe they are using the income from this issue, to pay for the huge losses from producing electric cars nobody wants.

 

[jameswilliam81991]

Hi Everyone. I experienced the NOx sensor issue together with my vehicle. I located a solution on the Xenons4u A brilliant recommendation exists to resolve your issue which I can offer to you.

 

[TC350]

@TC350 what OBD II tool do you use please?

 

[TC350]

Funnily enough I was just reading that myself. I'm now trying to figure out what £25 OBD tool the person is on about as it almost sounds too good to be true but definitely worth a go.

It’s under £20 from Amazon at the moment.

 

[TC350]

I was chatting to my local main dealer today and mentioned a suggestion of hard driving to keep the sensors clean …

I’ve suggested hard driving for just a couple of minutes every now and then.

 

[cws196]

It's not just the NOX sensors that fail in the AdBlue system (and I would not be using non-genuine MB parts in this instance based on advice from a friend who is an MB head-tech - he see's numerous cars that have had non-OE sensors fitted and the issue quickly returns after replacement so you end up having to buy genuine MB after all). For the past few years MB have been fitting updated NOX sensors and dealers should also perform install inconjunction with updated engine software - again, you're not going to get this with aftermarket sensors. Other issues include the following.

-The AdBlue injector furs up with crytalised urea and then blocks - this is located on the exhaust pipe and if you catch it in time you can easily clean off the deposits of crystalised urea.

-The AbBlue tank heaters fail or the AdBlue crystalises at the bottom of the tank, causing a blockage - no fix for the failed heater element but I was advised to not fill the tank more than 50% so you get a better through-flow.

 

[TC350]

It's not just the NOX sensors that fail in the AdBlue system (and I would not be using non-genuine MB parts in this instance based on advice from a friend who is an MB head-tech - he see's numerous cars that have had non-OE sensors fitted and the issue quickly returns after replacement so you end up having to buy genuine MB after all). For the past few years MB have been fitting updated NOX sensors and dealers should also perform install inconjunction with updated engine software - again, you're not going to get this with aftermarket sensors. Other issues include the following.

-The AdBlue injector furs up with crytalised urea and then blocks - this is located on the exhaust pipe and if you catch it in time you can easily clean off the deposits of crystalised urea.

-The AbBlue tank heaters fail or the AdBlue crystalises at the bottom of the tank, causing a blockage - no fix for the failed heater element but I was advised to not fill the tank more than 50% so you get a better through-flow.

Neither is it just NOx sensors in AdBlue systems that fail. I've had three genuine MB sets 'fail' on my petrol engine. I've been assured by MB that each time they've been replaced the software has been updated.

(I still suspect that none of them have actually failed, but rather that the software has erroneously declared that they've failed because they've temporarily crept out of arbitrarily prescribed limits.)

 

[JustmeJB]

Thanks for all the replies, much appreciated. I have some ramps now so am going to get under the car and see if I can remove the NOX sensor and adblue to clean them. I just find it hard to stomach that such a good brand of car has so many issues. I know others suffer too but Mercedes seem to be the biggest portion. It's making me consider another brand but the struggle would be which one. The other two options are leasing (not a fan if I'm honest) and buying an older car and having engine, suspension, bushes etc sorted to make it a comfy ride and reliable as can be.
I would like to keep the e class as it's a lovely car to drive but if it means many £k's spent on it each year then it's not sustainable.
I'm now researching OBD dongles to override the NOX etc.
I've given myself to the end of this year to find a solution or change vehicle.

 

[JustmeJB]

It’s under £20 from Amazon at the moment.

Cheers @TC350 can I ask if that device can be used on diesel cars. The description doesn't mention anything but one of the pictures says not so I suspect it could be a different model for diesel.

 

[cws196]

Thanks for all the replies, much appreciated. I have some ramps now so am going to get under the car and see if I can remove the NOX sensor and adblue to clean them. I just find it hard to stomach that such a good brand of car has so many issues. I know others suffer too but Mercedes seem to be the biggest portion. It's making me consider another brand but the struggle would be which one. The other two options are leasing (not a fan if I'm honest) and buying an older car and having engine, suspension, bushes etc sorted to make it a comfy ride and reliable as can be.
I would like to keep the e class as it's a lovely car to drive but if it means many £k's spent on it each year then it's not sustainable.
I'm now researching OBD dongles to override the NOX etc.
I've given myself to the end of this year to find a solution or change vehicle.

You can only remove the AdBlue injector to clean, not the NOX sensors. I'll just add as well that following replacement of both of my NOX sensors+software update on my C250d back in May 2023, I've had no issues since.

 

[TC350]

Cheers @TC350 can I ask if that device can be used on diesel cars. The description doesn't mention anything but one of the pictures says not so I suspect it could be a different model for diesel.

I think it's probably only pre 1996 diesel cars that it can't work on. Perhaps they didn't use OBD2. But I've never owned a diesel car (or had any interest in them) so I can't be certain.

 

[JustmeJB]

You can only remove the AdBlue injector to clean, not the NOX sensors. I'll just add as well that following replacement of both of my NOX sensors+software update on my C250d back in May 2023, I've had no issues since.

Interesting. I understood the NOX sensors can be removed (how does the main stealer change them?) to clean.
This is my second set of NOX sensors within 18 months with the associated software updates. Hence I'm rapidly loosing faith and looking for alternate solutions to funding the main dealer cafes/ games consoles/"free" refreshments that keep us entertained in the reception area whilst the work is getting done ;-) .
I really don't want to go down the system delete/remap route for obvious reasons.

 

[TC350]

Interesting. I understood the NOX sensors can be removed (how does the main stealer change them?) to clean.
This is my second set of NOX sensors within 18 months with the associated software updates. Hence I'm rapidly loosing faith and looking for alternate solutions to funding the main dealer cafes/ games consoles/"free" refreshments that keep us entertained in the reception area whilst the work is getting done ;-) .
I really don't want to go down the system delete/remap route for obvious reasons.

The NOx sensors can be removed for cleaning. I've read various reports on people doing it and seen a YouTube video of it.

I just find it a heck of a lot easier to spend a few minutes every year plugging in my OBD2 reader to cancel the code (which you'd have to do anyway after cleaning!)

 

[JustmeJB]

The NOx sensors can be removed for cleaning. I've read various reports on people doing it and seen a YouTube video of it.

I just find it a heck of a lot easier to spend a few minutes every year plugging in my OBD2 reader to cancel the code (which you'd have to do anyway after cleaning!)

Cheers. That's definitely the preferred option. I've just ordered a scanner off Amazon so I'll give it a go tomorrow when it arrives.

 

[TC350]

Cheers. That's definitely the preferred option. I've just ordered a scanner off Amazon so I'll give it a go tomorrow when it arrives.

If my experience is anything to go by, you'll just need to cancel the code 2 or 3 times over the coming month, then all will be fine for a year or so.

Good luck

 

[JustmeJB]

If my experience is anything to go by, you'll just need to cancel the code 2 or 3 times over the coming month, then all will be fine for a year or so.

Good luck

Hopefully I'll have a good result. I'll let you know.