Nox sensor fault

[MC220d]

Rang a garage and they saying they will only replace both?

Why would both need to be replaced if only one is faulty?

Surely the faulty one can’t damage the non faulty one?

 

[bladecrazy]

hi mate, its because when you fit the new style sensors the software is there to match that new sensor and wont work with the old style so changing both is needed.

 

[MC220d]

What an expensive job

Might have to delay getting it done

 

[bladecrazy]

It is expensive but unfortunatly if you have the mil light on then regens wont happen so if you continue to run it more problems will occur, these sensors are not fit for purpose and should be changed for free.

 

[MC220d]

Hi,

Further twist. I was told after I bought the car that the car had the dpf taken out(don’t know how true that is)

If the dpf is taken out, will the Nox sensor eml light come on?

Also, I guess there would be no point in fixing the Nox if it’s not doing anything?

P.s how would you know if the dpf has been taken out?

End of questions

 

[ajlsl600]

Do google search for dpf for yr model then go look under car for it..

 

[bladecrazy]

hi mate, strange that its throwing nox faults with no dpf, i would asume if there is no dpf then what would be the point of having nox sensors and adblue as they all work together. mine is at the back of the engine bay.

 

[MC220d]

hi mate, strange that its throwing nox faults with no dpf, i would asume if there is no dpf then what would be the point of having nox sensors and adblue as they all work together. mine is at the back of the engine bay.

Yeah that’s what I’m thinking. Will have to get a mechanic to test if it actually has a dpf or not. If it doesn’t, it will probably need remapping but my feeling is it does.

Thanks agaib

 

[Botus]

many gut the inside of the DPF (often as cheap maint dodge to clear a blocked one) and weld them up. Trouble is most MOT boys are quite clued up and like to fail them on this....

its quite a hot one for the undercover inspectors to spring on garages, to check if they are doing MOTs right. So most MOT places will pick you up on it, coz your misery is vastly offset by them losing their license

 

[MC220d]

many gut the inside of the DPF (often as cheap maint dodge to clear a blocked one) and weld them up. Trouble is most MOT boys are quite clued up and like to fail them on this....

its quite a hot one for the undercover inspectors to spring on garages, to check if they are doing MOTs right. So most MOT places will pick you up on it, coz your misery is vastly offset by them losing their license

I’ve had it pass MOT a few months ago so they may not have checked this aspect properly.

If what you say happens and that’s what has happened to my car, would there be any point in replacing the Nox? Would I need some sort of remap to stop the Nox being checked

 

[Botus]

no idea,

cars are far more complex than they used to be, diesels are nasty things and to make them less deadly they have complex emission control systems

DPF, a particulate trap, grabs much of the hideous cancer causing soot and sets fire to them to destroy the mess when needed
EGR, exhaust gas regeneration, a device that tries to clean the filth and make the heater work
Ad Blu, urea injection trying to reduce the Nitrous Oxide emissions killing the planet
SCR, a special catalyst part of the ad blue injection system

they all rely on each other to function correctly, its not one bit, they all have to be there working to make it drive right and get the emissions less deadly - if we cared about life on the planet we'd have banned them worldwide 10 years ago

 

[MC220d]

no idea,

cars are far more complex than they used to be, diesels are nasty things and to make them less deadly they have complex emission control systems

DPF, a particulate trap, grabs much of the hideous cancer causing soot and sets fire to them to destroy the mess when needed
EGR, exhaust gas regeneration, a device that tries to clean the filth and make the heater work
Ad Blu, urea injection trying to reduce the Nitrous Oxide emissions killing the planet
SCR, a special catalyst part of the ad blue injection system

they all rely on each other to function correctly, its not one bit, they all have to be there working to make it drive right and get the emissions less deadly - if we cared about life on the planet we'd have banned them worldwide 10 years ago

Knew I should’ve not got a diesel!!!

 

[Botus]

who says the DPF was removed - might just be an idea to get you to spend money ?

there are lots of things amiss with how the car was made... and some illegality and cheap parts where used, plus a number of interesting extras buried in the software designed to get you to take it back to Mercedes later in its life that they never expected an owner would find out about. EU and USA have been asking Mercedes to remove some special extras or they'll cut various things off the leadership team.

I particularly like the strange ambient temp reading affecting the way the engine runs, which appear to have been a subversive engineer allowing the emission fiddle to come to light in later years

the one bit missing in the post below is the ad blue tank can play up and need to be replaced rather than just a sensor... if it was the USA you'd get most of a car for free under a class action lawsuit but we prefer to pay in this country (trouble is 4 years is a long time away from being plugged in to germany so you have any servicing showing up as legit)

https://forums.mercedesclub.org.uk/index.php?threads/adblue-problem.186501/#post-1886807

these are USA ones... so possible we have others and or don't have these, top one is for w213 the bottom is w212 and there was at least three strange extras to come out of the later cars software

https://mbworld.org/forums/attachme...53122774-bulletins-213-ecu-os-temp-sensor.pdf

https://mbworld.org/forums/attachme...-212-sedan-mb-service-campaign-2019040001.pdf

 

[MC220d]

Very informative answer.

I’ve already had the car Ecu and Nox software updated by Mercedes with the recall.

They said my car Nox sensors aren’t the ones that they are replacing for free (no goodwill also as don’t have full merc service history)

Complained via customer services and some guy from Holland said nothing further they can do and won’t do.

 

[ajlsl600]

no idea,

cars are far more complex than they used to be, diesels are nasty things and to make them less deadly they have complex emission control systems

DPF, a particulate trap, grabs much of the hideous cancer causing soot and sets fire to them to destroy the mess when needed
EGR, exhaust gas regeneration, a device that tries to clean the filth and make the heater work
Ad Blu, urea injection trying to reduce the Nitrous Oxide emissions killing the planet
SCR, a special catalyst part of the ad blue injection system

they all rely on each other to function correctly, its not one bit, they all have to be there working to make it drive right and get the emissions less deadly - if we cared about life on the planet we'd have banned them worldwide 10 years ago

The makers have a responsibility to make the emissions equipment reliable at point of sale and where required,serviceable ,not simply capable of seeing warranty out..
I dont have an issue with maintenance but right now I see issue as makers fd up and are flat out making owners pay for that .if adblue pts were avail on a replace wots broke at reasonable cost I will as and when repair it.but whilst maker wants to stuff me with replace whole assly to get crxx sensor ,then its going to be a wriggle I look for. Same applies to the egr system .had I known how this stupid design worked I would have avoided it.its not fit for purpose as a maintainable system. Frankly designed to fail. But also designed to get vehicle out of warranty.

 

[bladecrazy]

for me it spoils the enjoyment of the car litterally waiting for the adblue heater/pump to go next, haveing already replaced my nox sensors at my own cost and now thinking how much is the next sting going to cost me. gaz

 

[ajlsl600]

In simple terms its an unreliable system and makers get away with screwing owners as IT has to work.
And as such ,unfortunately as long as this continues to be mode of operation there will continue to be shifty work arounds ..easily sorted.force makers to apply decent warranties on all emissions kit,and keep prices reasonable .
Result . ......
Emisions kit maintained by owners. Kit gets better made .lasts longer . Market for work arounds shrinks enviroment better off. Simples really.

 

[Benz Carl]

Hi, how much did u paid ?
Thx

 

[MC220d]

Hi, how much did u paid ?
Thx

I’ve just bit the bullet. After ringing around I’m paying approx £1400 for Nox sensor replacement, timing chain and tensioner.

Nox sensor - £660
Timing chain and tensioner - £720

Most places were saying something similar (maybe cheaper replacing Nox but then higher for timing chain) so getting it done.

My car is only a 2014 and it’s been an absolute nightmare with all these repairs. Couldn’t bought a better one with all the extra I have paid. But once done hopefully will last me a few years.

Ps and now I find that the cushion driver side heater doesn’t work but I’m leaving that. :-(

 

[mersum1es]

NOX / adblue devices has been absolutely PITA lately, I think they are not MB problem only since parts are made by other big companies ad all car manufacturers are using same harware.

If Nox sensor fault is not repaired, like said, it will prevent adblue to work. That p*ss injection system will be clogged if it is not used and will cause malfunction of whole adblue system. Which IS needed on MOT, otherwise than DPF... true, there are already 'emulators' for adblue too...