Recurring NOX sensor issue on 16 model C200 Coupe (petrol)

[Wighty]

Thanks for that! I just feel very much at the mercy of the dealer, getting blinded with science!
First step is "initial" diagnosis, which may lead to "in depth" diagnosis. I'll post the initial response.
In Somerset.
Meanwhile, the car (petrol) is performing fine

Good Indy in the form of Steve at Avantgarde Mercedes , Clevedon near Bristol .

 

[Big Burd]

Good Indy in the form of Steve at Avantgarde Mercedes , Clevedon near Bristol .

Hey thanks! That's good to know. A second informed opinion will help enormously.

 

[MKCambs]

Hi there, just an update from my side (original poster):

Amber engine warning light kept coming on, MB Cambridge suspected NOX sensor, reset the warning etc, but the issue kept coming back every few months. Eventually, on one occasion (about 4 months ago), I was asked by MB Cambridge to call (mobile) emergency assistance (because of lockdown), to have an initial look. At inspection during emergency assistance, a loose cable was found between the battery and the rest of the electrical system (don't know the exact location, sorry). Because of the loose connection, sometimes the voltage was peaking as a result of a spark etc. This was causing the electrical system to raise an alarm intermittently. When the cable was tightened, the problem seems be resolved (at least, so far).

Before, the car used to recharge very slowly (the recharge indication was yellow most of the time, seldom went green, only after a few hours of drive). It seems that that was a symptom of an issue with the electrical system. After the fix (cable tightened), now the car is recharging very quickly, after 10-15 min of drive.

So, it might be worth checking for loose connections in the electrical system/battery in case of the warning light issue occurring repeatedly.

 

[Big Burd]

Many thanks for that! Intriguing! Modern cars are great - until you try to track down an electrical/IT fault.
It'll be interesting to hear what MB S West have to say

 

[MKCambs]

Update:

Amber engine warning light came back on again a few weeks ago. This is the 14th time this happened with this car in the last 6 years!

Took the car to MB Cambridge (Group 1 Auto). They said the NOX sensor is faulty and needs to be replaced. They claim it is being caused by the car not driven long enough. This is what they claim:
"The issue with the NOX sensor keeps failing due to lack of mileage and the sensor needing a good gasoline particulate burn off AKA ''clearing out'' fairly often. The first 10ish minutes of driving is pretty much irrelevant for cars as the vehicle is still trying to wake up and warm up."

Basically they are trying to put the blame on the driver and get away with it (they want me to cover the cost) even though this has been a recurrent issue with this car, which started when it was under warranty.

I will keep pushing them and might have to take it to Motor Ombudsman or failing that to small claims court. It would be interesting to see what they would think about this.

I have a friend who owns a similar model and had a similar problem (faulty NOX sensor). He said that NOX sensor fault on those cars is a known issue within the industry. He had MB Cambridge fix it (replace the sensor) free of charge.

 

[Srdl]

I can’t see this is right - diesel, perhaps, but petrol cars shouldn’t have any problems with short journeys.

Have a look at this article which discusses GPFs in more detail and it might help you.

Infineum Insight - Gasoline particulate filters

Regulations curbing vehicle tailpipe emissions are being introduced and/or tightened the world over to help improve air quality. Infineum Insight looks at the automotive industry’s growing use of gasoline particulate filters as one method of compliance.

www.infineuminsight.com

Otherwise, I would do just what you are doing - MB Head Office UK, MB Customer Services in Europe, Motoring Ombudsman etc. Good luck!

 

[MKCambs]

I can’t see this is right - diesel, perhaps, but petrol cars shouldn’t have any problems with short journeys.

Have a look at this article which discusses GPFs in more detail and it might help you.

Infineum Insight - Gasoline particulate filters

Regulations curbing vehicle tailpipe emissions are being introduced and/or tightened the world over to help improve air quality. Infineum Insight looks at the automotive industry’s growing use of gasoline particulate filters as one method of compliance.

www.infineuminsight.com

Otherwise, I would do just what you are doing - MB Head Office UK, MB Customer Services in Europe, Motoring Ombudsman etc. Good luck!

Thank you for the useful information. I will read through it.

 

[Beemer2]

USA forum users have reported that the NOX sensor can be removed but sometimes with difficulty. It is then cleaned by soaking for a period in petrol. My independent dealer has told me that a failed sensor will result in a failed MOT so I will try that fix.

 

[A.J.]

My EML light has come on twice over the last year with a suspect Nox sensor, it has not been on for about two and a half months now. I have still got a Nox Sensor on order with MB for about six months so assuming my light stays off I might have a sensor that will help somebody out

 

[Beemer2]

Andy,
Is this truly a £500 item?
Ian

 

[A.J.]

Andy,
Is this truly a £500 item?
Ian

Unfortunately, yes

 

[Botus]

there were updates in the USA to cure fake EML warning's on petrols

they had delightfully introduced some deliberate fake faults to scam money from customers - I have posted the TIPS documents here multiple times but never got a response - the errors in the ENGINE map are triggered if you haven't used the car for a few weeks, because of erroneous info from the external temp sensor

that in itself is rather intriguing, as this was the method GM and Benz used to trigger the Diesel-gate bodge up (faking colder temps to fire up the cold engine map that drove properly)

 

[Srdl]

there were updates in the USA to cure fake EML warning's on petrols

they had delightfully introduced some deliberate fake faults to scam money from customers - I have posted the TIPS documents here multiple times but never got a response - the errors in the ENGINE map are triggered if you haven't used the car for a few weeks, because of erroneous info from the external temp sensor

that in itself is rather intriguing, as this was the method GM and Benz used to trigger the Diesel-gate bodge up (faking colder temps to fire up the cold engine map that drove properly)

I didn’t use my car for seven weeks this summer - and haven’t had any problems

 

[ajlsl600]

Dtf. Pal. Engines near bullet proof but all the bolt on crxp ain't
I drive my 50k miles ml250 with icarsoft permanently plugged in. Next time I see ablu and related I deleting it its just not fit for purpose .

 

[Botus]

I didn’t use my car for seven weeks this summer - and haven’t had any problems

I didn't say it was every model they made - and if the car is updated the fault goes away (from march 2019)


Mercedes-Benz USA, LLC A Daimler Company
News Channel Update | Vehicle Compliance & Analysis
IMPORTANT EXTENDED WARRANTY INFORMATION
Daimler AG (“DAG”), the manufacturer of Mercedes-Benz vehicles, has determined that on the various Model Year (“MY”) 2014 -
2018 Mercedes-Benz vehicles listed below, the engine control unit (ECU) software may not meet current specifications.

In certain circumstances when the vehicles are parked for a long duration, an erroneous activation of the “Check Engine Lamp” from the
outside temperature sensor might occur. In our continuing efforts to assure the proper performance of Mercedes-Benz products
and to ensure the satisfaction of our customers, the warranty for the ECU software in the subject vehicles has been extended
from the original 4 years/50,000 miles to 10 years/120,000 miles. This ECU software extended warranty is applicable to the
following vehicles:

Model Model Years Sales Designation
CLA-Class 2014 - 2017 CLA250, CLA250 4MATIC
GLA-Class 2015 - 2016 GLA250, GLA250 4MATIC
C-Class 2015 - 2018 C300 4MATIC, C 43 AMG,
C-Class Coupe 2017 - 2018 C300, C300 4MATIC, C43 AMG
C-Class Cabriolet 2017 - 2018 C 43 AMG
ML-Class 2015 ML400 4MATIC
E-Class 2015 – 2018 E300, E350, E400, E400 4MATIC, E43 AMG
E-Class Coupe 2015 – 2016 E400, E400 4MATIC
GLS-Class 2017 GLS450 4MATIC
GLE Coupe 2016 - 2018 GLE450 AMG,GLE 43 AMG
SLC-Class 2017 - 2018 SLC300 , SLC43 AMG
SLK-Class 2016 SLK300
SL-Class 2015-2018 SL400, SL450

In the event of an illuminated ”Check Engine Lamp” which leads to a diagnosis of a fault with the outside temperature
sensor, the following fault codes may be present:

Motor Electronics (ME) N3/10 P007128 (for M274/276LA engine) – Ambient Air Temperature Sensor Circuit “A’
Range/Performance signal bias level out of range/zero adjustment failure

or

ME N3/10 P007028 (for M270 engine) – Ambient Air Temperature Sensor Circuit “A’ signal bias level out of
range/zero adjustment failure

In this event, guided tests will be available in Xentry which will lead to the update of the engine control unit software.
The following damage codes may be used: 54 575 90 Update Engine Control Unit Software.

 

[Beemer2]

I didn't say it was every model they made - and if the car is updated the fault goes away (from march 2019)


Mercedes-Benz USA, LLC A Daimler Company
News Channel Update | Vehicle Compliance & Analysis
IMPORTANT EXTENDED WARRANTY INFORMATION
Daimler AG (“DAG”), the manufacturer of Mercedes-Benz vehicles, has determined that on the various Model Year (“MY”) 2014 -
2018 Mercedes-Benz vehicles listed below, the engine control unit (ECU) software may not meet current specifications.

In certain circumstances when the vehicles are parked for a long duration, an erroneous activation of the “Check Engine Lamp” from the
outside temperature sensor might occur. In our continuing efforts to assure the proper performance of Mercedes-Benz products
and to ensure the satisfaction of our customers, the warranty for the ECU software in the subject vehicles has been extended
from the original 4 years/50,000 miles to 10 years/120,000 miles. This ECU software extended warranty is applicable to the
following vehicles:

Model Model Years Sales Designation
CLA-Class 2014 - 2017 CLA250, CLA250 4MATIC
GLA-Class 2015 - 2016 GLA250, GLA250 4MATIC
C-Class 2015 - 2018 C300 4MATIC, C 43 AMG,
C-Class Coupe 2017 - 2018 C300, C300 4MATIC, C43 AMG
C-Class Cabriolet 2017 - 2018 C 43 AMG
ML-Class 2015 ML400 4MATIC
E-Class 2015 – 2018 E300, E350, E400, E400 4MATIC, E43 AMG
E-Class Coupe 2015 – 2016 E400, E400 4MATIC
GLS-Class 2017 GLS450 4MATIC
GLE Coupe 2016 - 2018 GLE450 AMG,GLE 43 AMG
SLC-Class 2017 - 2018 SLC300 , SLC43 AMG
SLK-Class 2016 SLK300
SL-Class 2015-2018 SL400, SL450

In the event of an illuminated ”Check Engine Lamp” which leads to a diagnosis of a fault with the outside temperature
sensor, the following fault codes may be present:

Motor Electronics (ME) N3/10 P007128 (for M274/276LA engine) – Ambient Air Temperature Sensor Circuit “A’
Range/Performance signal bias level out of range/zero adjustment failure

or

ME N3/10 P007028 (for M270 engine) – Ambient Air Temperature Sensor Circuit “A’ signal bias level out of
range/zero adjustment failure

In this event, guided tests will be available in Xentry which will lead to the update of the engine control unit software.
The following damage codes may be used: 54 575 90 Update Engine Control Unit Software.

Unfortunately my 2014 E250 is not listed.

 

[CaboSteve]

Been dealing with the same thing on my 2018 C200 Cab. Last year on long motorway drive after 2 hours amber Engine Check Light came on. ODB Code P2204 Intermittent NOx Sensor Bank#1. Reset it and gave the print out to my local Mercedes Dealer. They decided to let it go and not follow up saying it was likely a one time issue. No long drives again until a week ago and again after 2 hours on motorway ECL came on again and code P2204 set. Taking car into dealer today to have them diagnose it. This time have not reset the ECL so they can see for themselves the ODB code. Will report back later

 

[Julieoscar]

Not had this issue personally and not heard much on petrol cars either. (On diesels contamination might cause it I guess ). Interesting to hear what others say on this, I wonder on the low mileage whether temperature shock could be knocking the sensor out or something CAT related?
Oh and on warranty, any reported issue which is on going should still have cover but I’d flag this to MB

Hi I reported this problem a few years ago , I bought my 2016 E 220 from Robinsons in Cambridge too and also had nox sensor problems . I had them replaced twice under the two year warranty , then I paid £600 to replace both of them ( even though Mercedes replaced them separately ) they said they should have been done together ! My car was bought at 2 years old with 18 k miles and I hardly drove it at all after that .
After a few months I had the engine light again and I was told I needed a £6000 turbo replacement . I eventually paid off the finance and took it to an independent garage . Still got sensor problems but my main problem now is the ad blue fault , 4 times now and. counting . I’m just off to collect it this morning as I’ve had the ad blue filter cleaned and fault reset , I also requested they change the bulb in the LED front light , the long thin one ……obviously being Mercedes it’s not that simple and I have to change the whole light fitting at a cost of £1200 , I think that was just for the light ! If my son who is here for a few months didn’t need it for work I would happily take a sledgehammer to it , that car is just a heap of misery .

 

[ajlsl600]

I had the same problem of engine maintenance light on dashboard. Nox sensor error on c200 2014 petrol . Replaced once within one year. Same error now. Croydon Mercedes charging me around £600 for replacing it as it is now out of warranty period. I don't do many miles. Seems to be a systematic fault on these models.

Sticker on cars in showroom shud say don't buy me unless you do 20k miles a Yr and thrash car every Sunday.
Will benz every get their emissions kit properly sorted?
It's possible othe makes have same issues, however I don't own them. No other car I ever buy will have any of this crxp on them.

 

[bladecrazy]

I think most modern dervs are the same, they need to be used, all dealers should advise if buying a diesel regards mileage etc, would save a lot of headache further on.