Intermittent NOx Issue

SuffolkSifter

Active Member
Joined
Jul 9, 2020
Messages
96
Location
Ipswich, Suffolk
Car
ML350
Hi all,

I am here with this old chestnut. I have read some posts on here and elsewhere regarding NOx sensor replacement.

I have a 2012 ML350 (W166) with 59.697 mile which I had an EML one earlier this month, I read the code and it was a historical fault, that I cleared.

"111B00
State: Historic
Component 'NOx concentration upstream of the SCR catalytic converter' has a plausibility error".

I didn't see it again until I was en route to have my ML serviced by a Indi Merc Specialist yesterday, then it came on. They checked/reset it and took it out on a test drive with diagnostic equipment connected and said the values were OK, but that the NOx sensor has an intermittent fault and the EML may come on again. He advised me that I should contact my Merc dealer as this is very common failure and people have had the replaced FOC.

Is it worth getting in touch with MB?
 

C7pg

Member
Joined
Jan 30, 2017
Messages
41
Location
New Forest
Car
E220CDI Bluetec AMG line estate
On a car that age I'd say don't bother. They wouldnt help on my 2015 W212 when a Nox sensor failed recently despite full MB service history. Cost was eyewatering.
 

knighterrant

MB Enthusiast
Joined
Mar 2, 2012
Messages
5,599
Location
Cambridgeshire
Car
2012 C350 Sport with M276 engine
I think that C7pg is probably right. I had the NOx sensors on my 2012 C350 replaced by Mercedes in 2019 and discounted by £1000 after discussions with MBUK. At that time the car had covered less than 30k and had a full MB service history. Even before Mercedes would start discussing any potential goodwill gestures you'd have to pay to get them to do a test, which wouldn't tell you any more than you already know and is unlikely to result in any help from them.
 

knighterrant

MB Enthusiast
Joined
Mar 2, 2012
Messages
5,599
Location
Cambridgeshire
Car
2012 C350 Sport with M276 engine
Just got an email from MB saying that a goodwill payment is available, but I have to pay for diagnostic first.
Did you get your NOx sensor sorted? Did MB provide a goodwill payment?

My EML just came on again this morning. My code reader said “

P2214 - NOx Sensor Circuit Range/Performance Bank 2​

It’s less than 21 months and 5,000 miles since MB replaced both sensors! It means that they’re still under warranty but I suspect they’ll insist that I pay their exorbitant fee to tell me exactly the same thing before they’ll do anything. I still have three months parts warranty to play with so I think I’ll hang on a bit to see if the other sensor comes up with a fault and get them both changed at the same time.
 
OP
OP
SuffolkSifter

SuffolkSifter

Active Member
Joined
Jul 9, 2020
Messages
96
Location
Ipswich, Suffolk
Car
ML350
The say that they will ring me to make a booking but never do. The EML is on again, but now I know what is.
 

tombell

Member
Joined
Oct 21, 2020
Messages
48
Location
Oxford
Car
ML 250 W166 2012. E220 Coupe C207 2012. E220 2007
Hi all,

I am here with this old chestnut. I have read some posts on here and elsewhere regarding NOx sensor replacement.

I have a 2012 ML350 (W166) with 59.697 mile which I had an EML one earlier this month, I read the code and it was a historical fault, that I cleared.

"111B00
State: Historic
Component 'NOx concentration upstream of the SCR catalytic converter' has a plausibility error".

I didn't see it again until I was en route to have my ML serviced by a Indi Merc Specialist yesterday, then it came on. They checked/reset it and took it out on a test drive with diagnostic equipment connected and said the values were OK, but that the NOx sensor has an intermittent fault and the EML may come on again. He advised me that I should contact my Merc dealer as this is very common failure and people have had the replaced FOC.

Is it worth getting in touch with MB?
Bought a 62 Plate Merc ML at the beginning of May. A week ago I got message something like "1,700 miles before AdBlue runs out". I filled AdBlue to the brim. EML light still on. Tried all the tricks on the web to turn it off. No Go. Next day "600 miles engine won't restart". Took it to MB Oxford today. They are getting 2 Nox sensors for the end of the week. They want £1,871.52. and will have to remove exhaust. 3.8 hours
 

JanAlb

New Member
Joined
Jun 11, 2021
Messages
1
Location
Kingswinford
Car
C class convertible 250d 2017
Hi all,

I am here with this old chestnut. I have read some posts on here and elsewhere regarding NOx sensor replacement.

I have a 2012 ML350 (W166) with 59.697 mile which I had an EML one earlier this month, I read the code and it was a historical fault, that I cleared.

"111B00
State: Historic
Component 'NOx concentration upstream of the SCR catalytic converter' has a plausibility error".

I didn't see it again until I was en route to have my ML serviced by a Indi Merc Specialist yesterday, then it came on. They checked/reset it and took it out on a test drive with diagnostic equipment connected and said the values were OK, but that the NOx sensor has an intermittent fault and the EML may come on again. He advised me that I should contact my Merc dealer as this is very common failure and people have had the replaced FOC.

Is it worth getting in touch with MB?
I am having same issues . Took my c class convertible 2017 for service then a week later engine light came on . Took it back to garage they checked and said it was the nox. Contacted mb uk who have booked in to have another diagnostic which is costing £120 to probably tell me exactly what I already know . Trouble is there are no parts available at the mo and it could be months till they are available ! Shocking
 

tombell

Member
Joined
Oct 21, 2020
Messages
48
Location
Oxford
Car
ML 250 W166 2012. E220 Coupe C207 2012. E220 2007
I had to wait a week for the garage to receive the nox sensors from Merc. The garage fitted them but the message wouldn't go away. They had to take it to Merc Dealer to have it sorted
 

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