W205 NOX sensors

Cgd

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hi everyone

I was very happy with my new winter alloys, tyres, break pads and an A service last week. Car was a bit noisier due to the winters but all good


Took car in a long-ish second drive (each of around 120 miles, return) and after 25 minutes got an EML

Phoned dealer and got a no-nonsense priority appointment for the following morning (as I was away)

After 20 minutes the servicing guy comes back and tells me the fault is a NOX sensor Naively I ask if they could replace it there and then


He says the car is just out of warranty by a “couple o months” (going to check this against receipt as it was registered January 2016) and that each sensor is around £300!!!

I naturally gulp, and he says he needs to speak to the duty manager Returns with the news that in principle they’ll cover it under warranty as a gesture of good will, but that the branch manager has to sign it off ok Monday


So far is booked for Thursday, do any of you have similar experiences (as I’ve read some limited info about em online, just a few horror stories but nothing clear (at least to me) on what may be happening)

-what’s the standard warranty when it comes to these sensors?

-I’m told I can carry on driving till Thursday without issues So what do these NOX sensors do and why they matter?!

Thanks in advance!
 

ernieh

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hi everyone

I was very happy with my new winter alloys, tyres, break pads and an A service last week. Car was a bit noisier due to the winters but all good


Took car in a long-ish second drive (each of around 120 miles, return) and after 25 minutes got an EML

Phoned dealer and got a no-nonsense priority appointment for the following morning (as I was away)

After 20 minutes the servicing guy comes back and tells me the fault is a NOX sensor Naively I ask if they could replace it there and then


He says the car is just out of warranty by a “couple o months” (going to check this against receipt as it was registered January 2016) and that each sensor is around £300!!!

I naturally gulp, and he says he needs to speak to the duty manager Returns with the news that in principle they’ll cover it under warranty as a gesture of good will, but that the branch manager has to sign it off ok Monday


So far is booked for Thursday, do any of you have similar experiences (as I’ve read some limited info about em online, just a few horror stories but nothing clear (at least to me) on what may be happening)

-what’s the standard warranty when it comes to these sensors?

-I’m told I can carry on driving till Thursday without issues So what do these NOX sensors do and why they matter?!

Thanks in advance!

First of all, they control the injection of AdBlu to control the NOx emissions and there are two of them. THey have been updated a number of times, so depending on when your car was made, they might have to replace both.
Mine went wrong 2 weeks out of warranty, but I had extended the warranty so I didn't have to pay. However, there have been instances on here when they have been done under goodwill and others when MB refused; it seems to depend on how willing your dealership is to fight your corner. It sounds as though your dealer is sympathetic, so you might be lucky........

Ernie

ps, Just noticed that your car was registered Jan 2016; if that is the case, you should be covered under Manufacturer's Warranty.
 
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Cgd

Cgd

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First of all, they control the injection of AdBlu to control the NOx emissions and there are two of them. THey have been updated a number of times, so depending on when your car was made, they might have to replace both.
Mine went wrong 2 weeks out of warranty, but I had extended the warranty so I didn't have to pay. However, there have been instances on here when they have been done under goodwill and others when MB refused; it seems to depend on how willing your dealership is to fight your corner. It sounds as though your dealer is sympathetic, so you might be lucky........

Ernie

ps, Just noticed that your car was registered Jan 2016; if that is the case, you should be covered under Manufacturer's Warranty.
Much appreciated Ernie, fingers crossed!
 
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Cgd

Cgd

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Hi ernieh

Thanks again for your support


The resolution has a happy ending but I do wonder what the deal is!


Car has had the two NOX sensors replaced and a epuc (or similar, can’t remember the name). They were all done under warranty, I had no charge but also they wouldn’t produce any paperwork (most bizarre!).

I’ve made a note of all the different events and hope for the best!

I sincerely hope it works as I didn’t go for a Merc to be at garages so often!

I forgot to say, the car is only 30K gentle mileage old!
 

ernieh

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Hi ernieh

Thanks again for your support


The resolution has a happy ending but I do wonder what the deal is!


Car has had the two NOX sensors replaced and a epuc (or similar, can’t remember the name). They were all done under warranty, I had no charge but also they wouldn’t produce any paperwork (most bizarre!).

I’ve made a note of all the different events and hope for the best!

I sincerely hope it works as I didn’t go for a Merc to be at garages so often!

I forgot to say, the car is only 30K gentle mileage old!
It’s not unusual for them not to issue paperwork on warranty jobs as they look on MB as the customer since they are paying. Work carried out will be held on record though, so if you speak nicely to them, they may give you a print out for your records.

For interest my NOx sensors failed at 22k miles.

Ernie
 

CJD

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I recently traded in my E350 Coupe, the EML came on in the period leading up to the change over.
Both NOX sensors where found to be faulty, and where changed FOC by the dealer.
The service manager told me they have changed literally thousands of them, and it is a well known problem.
He said that the design has been changed, and that rather than issue a recall MB are just changing them FOC as and when the originals fail, some only last 6 weeks and others 60K miles - my E350 had done 54K so was at the upper limit.
 


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