Nox sensor and exhaust

[Paul Edgecombe]

Hi all, I have a 2016 CLS 220D Shooting Brake. The engine warning light came on and I have had the problem diagnosed as a Nox sensor failure. My local garage got a sensor in for me but cannot get the old one out of the exhaust. I have taken the car to a Mercedes specialist and they have quoted me £2640 to replace the centre part of the exhaust and Nox sensor. I wonder if anyone else has had this problem and how to get around this vast cost. This problem arose almost immediately after Mercedes recalled my car and updated the software. The car hasn't done 32000 miles yet. Of course Mercedes tell me it is nothing to do with the upgrade. Thanks

 

[malcolm E53 AMG]

You are not on your own quite a few members on here have suffered the same Nox sensor failures after the diesel emissions software update in fact a lot of owners won’t let Mercedes touch the car due to this myself included although I’ve just sold my diesel car and won’t be buying another. I’d do some research on here and go back to MB and ask for some goodwill you are ‘not the only one’ this is a known problem and you are being fobbed off.

 

[ajlsl600]

A well trot path of woe.

 

[onefortheroad]

Can the garage not heat it up and get it out , worse case scenario would be maybe helicoil if applicable?

 

[mioba]

Wire brush, plus gas for 2 weeks. Then maybe resort to the blow torch.
Patience is key to seized bolted fittings.
You go in ham fisted, you will round, snap it.
Tighten loosen in increments spray so on ans so forth.

 

[davidsl500]

There's always a way. If it won't budge, drill out, helicoil/re-tap or even drill hole in exhaust near sensor plug, weld correct thread nut on pipe and screw in sensor.. You need an old fashioned mechanic!

 

[Paul Edgecombe]

Just an update, A Mercedes specialist tried to get the Nox sensor out and failed. The car is now at the local Mercedes main agents and they tell me that they have a specialist they can call on who may be able to remove it. Now the news gets even worse as they tell me that Mercedes have changed the Nox sensors for a new type that are not compatible with the existing ones. So now I have to have both changed at £550 each plus £278 fitting each plus £250 for the specialist, and if the the exhaust gets damaged that will be another £1100 plus £440 fitting. they also charged me £122 for the diagnosis. So a failed sensor could end up costing me £3568. As soon as it is fixed it goes in PX.

 

[bladecrazy]

thats crazy!

 

[kleroo]

That's crazy!!!! What happened at last?

 

[tode]

Hi Paul,
If you do a search, you'll find a Mercedes document that clearly states that if the NOx sensors need to be changed after the update, then that will be done free as part of the update work. I had the same problem after they did a sneaky update during the last service.
If I can find the document, I'll post it up.

Here's a link to the English version of the Mercedes document: DIESEL UPDATE

 

[kleroo]

Hi Paul,
If you do a search, you'll find a Mercedes document that clearly states that if the NOx sensors need to be changed after the update, then that will be done free as part of the update work. I had the same problem after they did a sneaky update during the last service.
If I can find the document, I'll post it up.

Here's a link to the English version of the Mercedes document: DIESEL UPDATE

Any guess about the elapsed time? I just checked and mine was done earlier (with a different owner) Now I'm having nox issues... but I guess even 4-5 years has passed since the update. Can I still arrange a free fix? All I know for sure, is that it wasn't changed