Mercedes 2016 CLS - U029D Lost communication with N0x sensor A - Dealer claiming water damage

[platforminc]

Hi All.

I recently got this error on my CLS back in February, having had some work done by the dealer just under 12 months ago when they changed the Nox sensor under recall, I thought the right thing to do was to call them up to book an inspection since they changed the sensor just under a year ago, I took the car there today only for them to tell me that they need an extra hour for diagnostics, they found the front footwell soaked up with water and they claimed this could have likely affected the Nox sensor and hence the reason for the error.

I find it hard to believe that the front footwell was soaked up with water, there is a rubber mat there, I never smelt anything and there is no one that would have soaked it up with water. I just find it hard to believe, now the first hour of diagnostics is charged at over 200 quid and they want me to authorize another hour, after which they are likely to tell me that the issue was caused by faulty electrics caused by water damage.

Any ideas what I can do here ?

 

[Blobcat]

The Nox sensor isn’t in the footwell…

The footwell could well be damp if your scuttle drains are blocked, the Nox sensor is nailed into the exhaust which could get wet from road already… although as part of the design it should be able to cope with that.

I’d be wanting a written explanation as to how a damp footwell could cause a Nox sensor failure. Then take it up with the motor ombudsman if they get silly with you

 

[platforminc]

The Nox sensor isn’t in the footwell…

The footwell could well be damp if your scuttle drains are blocked, the Nox sensor is nailed into the exhaust which could get wet from road already… although as part of the design it should be able to cope with that.

I’d be wanting a written explanation as to how a damp footwell could cause a Nox sensor failure. Then take it up with the motor ombudsman if they get silly with you

Thank you very much for the reply, I am very grateful.
My dilemma now is this, the car is with the dealership, we are at a stalemate currently. They want me to pay for another hour of investigation, as it stands I am signed up to pay them £220 or so for diagnostics because apparently the Nox may or may not be under a recall, they need diagnostics to be done first to ascertain the issue if its one under a recall then I pay nothnig, if its something different then I have to pay for the diagnostics and from the call I got today, sounds like the latter. I can't leave the car there forever, if I go there to pick up the car, they will probably want to charge the £220 and I will still not have the answers nor a solution.

The claim is that there are electrics under the footwell, and some of those electrics relate to the Nox sensor, therefore the damp footwell has damaged the Nox sensor electrics. That was the line I got from them during the telephone call today.

What do I do ?

 

[onefortheroad]

Thank you very much for the reply, I am very grateful.
My dilemma now is this, the car is with the dealership, we are at a stalemate currently. They want me to pay for another hour of investigation, as it stands I am signed up to pay them £220 or so for diagnostics because apparently the Nox may or may not be under a recall, they need diagnostics to be done first to ascertain the issue if its one under a recall then I pay nothnig, if its something different then I have to pay for the diagnostics and from the call I got today, sounds like the latter. I can't leave the car there forever, if I go there to pick up the car, they will probably want to charge the £220 and I will still not have the answers nor a solution.

The claim is that there are electrics under the footwell, and some of those electrics relate to the Nox sensor, therefore the damp footwell has damaged the Nox sensor electrics. That was the line I got from them during the telephone call today.

What do I do ?

You could as a last resort if you don't want to splash the cash , have the Nox sensors deleted from the ECU around £200 to £300 .

 

[ajlsl600]

I am really sic of reading about benz nox sensors and related issues. I had scheduled delete a month ago but other events wrecked that plan, now rescheduled for next week.
Simply put I am deleting adblue and egr. Not because I really want to, rather that as adblue and egr is a bodge (benz anyway ( having had adblue system replaced 3 months before I bought car) at 1200 quid!
The simple facts are benz can't, won't make it work properly, my choices seem to be throw another 1200 at it ( and maybe end up with loads more shxte software issues , sell and prob get a 4,5k smack in mouth. Or delete it and be able to go about my business without constantly stressing about being 520 miles into France with a 500 to go dash warning its happened 3 times (I have been able to reset it), sometimes for up to 4k miles, for how long?
I don't modify my cars ever, until now, once done I will keep car until it, I die. I have, will, reinstate the system, one. If a sensible functioning work around appears, or mot brings in a test. Or if I choose to sell, I will offer buyer the choice
As is its simply a looming disaster to take an adblue car, benz anyway, to the larger EU.
Recovery costs? Language issues, getting it sorted in Europe, hire cars. Fd plans.
On emissions. Whist the poles, rumainians and others are sticking to their coal burning plans amoung others I do wonder on the point in stressing over it. The whole issue goes away if makers are forced(recall) to properly fix THIER F. U. The exisiting adblue kit is only 4 Yr old and the car is just over 68k miles.
Perhaps I shud go to benz with the b invoice. I just fear the likely hassle of any software update then bringing on another basket of headaches.
INCIDENTLY I HAVE CHEKED WITH MB there is no recall on my car related to brake servo or emissions equipment.??

 

[LostKiwi]

Brake servo was W164 based cars. Yours is a W166.

Ditto emissions.

 

[ajlsl600]

OK. So I am to assume my codes, messages that periodically appear ref nox, adblue are not considered, by benz, to be much to do with crxp sensors and or software and that post 164 the issues were solved?

 

[Steve@Avantgarde]

This is absolutely common on E class and CLS and I believe there is a TIPs document on this about water ingress into wiring. We have certainly done a few.

It has absolutely nothing to do with the NOx replacement and if you have a blocked scuttle that is ingressing water into the footwell then you wouldn't notice anything externally as the water will run down the bulkhead and under the carpet where the foam backed carpet will start to absorb the water and then saturate the wiring.

The only thing I don't agree with is the Labour charges of your dealer and the times they are quoting. To read the fault memory and carry out the guided test of the NOx test for wiring checks will take about half an hour. To remove the 2 trims on the side and pull the carpet forward and giving an inspection of the wiring should take only another half hour.

Removing the carpet, drying it properly and repairing and water damaged wiring (yes there maybe more as that is chassis CAN network and SRS territory) will take approx 4-5 hours of additional labour.

 

[ajlsl600]

Anyway hope op gets a good solution. Don't you guys think that benz design whereby any invisable blocked drain default is to soak interior and wiring is shxte design god help space exploration if benz get involved better Fred from his shed!!!!!

 

[Steve@Avantgarde]

Anyway hope op gets a good solution. Don't you guys think that benz design whereby any invisable blocked drain default is to soak interior and wiring is shxte design god help space exploration if benz get involved better Fred from his shed!!!!!

Your house would flood if the drains blocked, is that a poor design too?

A car will never be watertight above its shut lines but we aren't talking about a cup of water here, it will probably be around 5L of water which will be a mixture of rain water and screen wash. If you keep your car cleaned properly and don't park it under trees etc, you'll be ok.

 

[Steve@Avantgarde]

I am really sic of reading about benz nox sensors and related issues. I had scheduled delete a month ago but other events wrecked that plan, now rescheduled for next week.
Simply put I am deleting adblue and egr. Not because I really want to, rather that as adblue and egr is a bodge (benz anyway ( having had adblue system replaced 3 months before I bought car) at 1200 quid!
The simple facts are benz can't, won't make it work properly, my choices seem to be throw another 1200 at it ( and maybe end up with loads more shxte software issues , sell and prob get a 4,5k smack in mouth. Or delete it and be able to go about my business without constantly stressing about being 520 miles into France with a 500 to go dash warning its happened 3 times (I have been able to reset it), sometimes for up to 4k miles, for how long?
I don't modify my cars ever, until now, once done I will keep car until it, I die. I have, will, reinstate the system, one. If a sensible functioning work around appears, or mot brings in a test. Or if I choose to sell, I will offer buyer the choice
As is its simply a looming disaster to take an adblue car, benz anyway, to the larger EU.
Recovery costs? Language issues, getting it sorted in Europe, hire cars. Fd plans.
On emissions. Whist the poles, rumainians and others are sticking to their coal burning plans amoung others I do wonder on the point in stressing over it. The whole issue goes away if makers are forced(recall) to properly fix THIER F. U. The exisiting adblue kit is only 4 Yr old and the car is just over 68k miles.
Perhaps I shud go to benz with the b invoice. I just fear the likely hassle of any software update then bringing on another basket of headaches.
INCIDENTLY I HAVE CHEKED WITH MB there is no recall on my car related to brake servo or emissions equipment.??

NOx and adblue faults are not limited to Benz, its across every manufacturer in the industry. The issues started with diesel gate, which originated at Bosch who write most the control software for most manufacturers. In fact there are only 5 major players in this market and they were all in on it due to the emissions demands placed on manufacturers by worldwide governments.

Why do you think no car manufacturer claimed the moral high ground when VW were busted tricking control systems? Because everyones software was compromised because it came from virtually the same source or a derivative of it.

 

[ajlsl600]

OK get that but even after how many stories it still don't work properly. In my view it likely never will. That understood the 500 mile thing should change to no mot if not working and bosch or maker being forced to make it reliable or replace with another system that does work properly.

 

[platforminc]

This is absolutely common on E class and CLS and I believe there is a TIPs document on this about water ingress into wiring. We have certainly done a few.































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































It has absolutely nothing to do with the NOx replacement and if you have a blocked scuttle that is ingressing water into the footwell then you wouldn't notice anything externally as the water will run down the bulkhead and under the carpet where the foam backed carpet will start to absorb the water and then saturate the wiring.































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































The only thing I don't agree with is the Labour charges of your dealer and the times they are quoting. To read the fault memory and carry out the guided test of the NOx test for wiring checks will take about half an hour. To remove the 2 trims on the side and pull the carpet forward and giving an inspection of the wiring should take only another half hour.































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































Removing the carpet, drying it properly and repairing and water damaged wiring (yes there maybe more as

that is chassis CAN network and SRS territory) will take approx 4-5 hours of a Idditional labour.







































Thanks























































































































































































































































































































































































































































































Ok. Thanks for this.































































































































I'm unsure about the next step as you have mentioned that the water ingress has nothing to do with wiring but also suggesting that the water ingress could cause a nox error.







This is absolutely common on E class and CLS and I believe there is a TIPs document on this about water ingress into wiring. We have certainly done a few.







It has absolutely nothing to do with the NOx replacement and if you have a blocked scuttle that is ingressing water into the footwell then you wouldn't notice anything externally as the water will run down the bulkhead and under the carpet where the foam backed carpet will start to absorb the water and then saturate the wiring.







The only thing I don't agree with is the Labour charges of your dealer and the times they are quoting. To read the fault memory and carry out the guided test of the NOx test for wiring checks will take about half an hour. To remove the 2 trims on the side and pull the carpet forward and giving an inspection of the wiring should take only another half hour.







Removing the carpet, drying it properly and repairing and water damaged wiring (yes there maybe more as that is chassis CAN network and SRS territory) will take approx 4-5 hours of additional labour.



This is absolutely common on E class and CLS and I believe there is a TIPs document on this about water ingress into wiring. We have certainly done a few.



It has absolutely nothing to do with the NOx replacement and if you have a blocked scuttle that is ingressing water into the footwell then you wouldn't notice anything externally as the water will run down the bulkhead and under the carpet where the foam backed carpet will start to absorb the water and then saturate the wiring.



The only thing I don't agree with is the Labour charges of your dealer and the times they are quoting. To read the fault memory and carry out the guided test of the NOx test for wiring checks will take about half an hour. To remove the 2 trims on the side and pull the carpet forward and giving an inspection of the wiring should take only another half hour.



Removing the carpet, drying it properly and repairing and water damaged wiring (yes there maybe more as that is chassis CAN network and SRS territory) will take approx 4-5 hours of additional labour.

This is absolutely common on E class and CLS and I believe there is a TIPs document on this about water ingress into wiring. We have certainly done a few.

It has absolutely nothing to do with the NOx replacement and if you have a blocked scuttle that is ingressing water into the footwell then you wouldn't notice anything externally as the water will run down the bulkhead and under the carpet where the foam backed carpet will start to absorb the water and then saturate the wiring.

The only thing I don't agree with is the Labour charges of your dealer and the times they are quoting. To read the fault memory and carry out the guided test of the NOx test for wiring checks will take about half an hour. To remove the 2 trims on the side and pull the carpet forward and giving an inspection of the wiring should take only another half hour.

Removing the carpet, drying it properly and repairing and water damaged wiring (yes there maybe more as that is chassis CAN network and SRS territory) will take approx 4-5 hours of additional labour.

Hi.

Thanks for the reply. I'm confused by the response. Could the wet footwell cause the nox error it it can't?

On one hand your response suggests it could and on the other hand it says it has nothing to do with nox.

 

[ajlsl600]

It's components and wiring passing thruu the footwells that cause some issues
And the default of knowingly sending water from blocked drains to there that is the issue
Most owners wud hav no idea that water was getting to those components until too late( stupid design as above being a known case, and it is), the components should all be waterproof. That costs money, as does a redesign that prevents any water getting there in the first place. It may be the case but I have not read about dacia dusters 20k having flooded foot well electrics. The illusion of quality, AGAIN.

 

[platforminc]

I have now heard back from Merc, they want 1400 + 420 diagnostics to sort this out.
According to them, this is what they have written as the root cause.


water leak found from seam seal. this has caused water to run through wiring loom into nox sensor causing engine light on dash. reapir required to seam seal + replacment wiring loom and nox sensor required.

The red circled section is underneath the car, there is a wiring loom there which connects from the front passenger footwell and ends up here. probably powers the sensor.





On this picture below. The red circle is water within the footwell which has managed to get into the connector circled in blue.




The questions I have at this point are as follows.

What can I do to fit the vehicle.
I dont believe the wiring loom is damaged, I think it just needs to be disconnected and dried out with the source of the water ingress fixed.
Does anyone know the MB part number for the front NOX sensor for a 2016 220 Bluetec CLS.
Does anyone know a good reasonably priced independent within the SE London or Kent area or any other areas in London. I am happy to travel

Any other thoughts please.

Thankls.

 

[Srdl]

Does anyone know a good reasonably priced independent within the SE London or Kent area or any other areas in London. I am happy to travel

@alexanderfoti at AMF Automotive https://www.amfmercedes.com is near Tonbridge, I believe. Hopefully, he will see this and add his views.

 

[alexanderfoti]

I will add my thoughts tomorrow morning.
Long day today and sleep is imminent

 

[Uncle Benz]

I have now heard back from Merc, they want 1400 + 420 diagnostics to sort this out.
According to them, this is what they have written as the root cause.


water leak found from seam seal. this has caused water to run through wiring loom into nox sensor causing engine light on dash. reapir required to seam seal + replacment wiring loom and nox sensor required.

The red circled section is underneath the car, there is a wiring loom there which connects from the front passenger footwell and ends up here. probably powers the sensor.

View attachment 83325



On this picture below. The red circle is water within the footwell which has managed to get into the connector circled in blue.

View attachment 83326


The questions I have at this point are as follows.

What can I do to fit the vehicle.
I dont believe the wiring loom is damaged, I think it just needs to be disconnected and dried out with the source of the water ingress fixed.
Does anyone know the MB part number for the front NOX sensor for a 2016 220 Bluetec CLS.
Does anyone know a good reasonably priced independent within the SE London or Kent area or any other areas in London. I am happy to travel

Any other thoughts please.

Thankls.

Is there actually a connector there within the blue circle? It’s very unlike Mercedes to have two connections on a cable. It’s obviously got a connection at the NoX sensor, but for that to be an extension loom? I doubt it. The grommet in the floor there looks big enough to pass the plug through that fits to the NOx sensor. I’d be going down there for a look myself. If it’s wires all the way through to the sensor I’d doubt water can get in there to mess it up

 

[platforminc]

Is there actually a connector there within the blue circle? It’s very unlike Mercedes to have two connections on a cable. It’s obviously got a connection at the NoX sensor, but for that to be an extension loom? I doubt it. The grommet in the floor there looks big enough to pass the plug through that fits to the NOx sensor. I’d be going down there for a look myself. If it’s wires all the way through to the sensor I’d doubt water can get in there to mess it up

Apologies for the poor quality of the photo, I had to screenshot the video sent to me. From looking at the video it appears as though there is a grommet there with some cables and those cables might be going underneath the car towards the nox sensor.

I could be wrong, but the only way to tell again is to take it all apart and check myself.

 

[ajlsl600]

Check yrself is often the most economic path. Yr saying water in footwell, cos of shxte design, has passed thru grommet and ran into nox sensor if poss try drying everything out and try again. The sensor wires should be well sealed into sensor, after all it is UNDER the car.