Cris Kalas

I just received a new one that is about the catalytic converter system. Any chance you can share with us a similar document to the one you uploaded about the valves? This way we can see what are the service instructions towards the dealerships.

MB Miami told me today that the car needs to have an MIL for 0430 and 0420 Catalyst system efficiency below threshold.

If the MIL is about fuel trims due to restricted cats on their way out, they won’t cover them even though we are talking about the same part being faulty.

I contacted MBUSA and they didn’t know anything about specific codes.

Thanks in advance.

nkx1

Is this an indication that 2017+ M278 engines were improved in some meaningful capacity?

Sachant18

Yes they have been improved, the coating has improved and also the quality inspection of the faulty presses at the MB engine Factories have improved.
Besides the liner coating, the biggest issue was that the presses who produced the cylinder heads where faulty pressing the valve seats into the cylinder head.
From 2016 the engines have improved.
I had a late 2014 2015 model, and shortly after my M278 MB figured that they had issues, but it took them a while as also the AMG M278 version was impacted.
I have a new M278 under the extended warranty, it drives like a dream!

BlownV8

What AMG runs a M278? Do you have any official press releases to verify the rest of what you are saying?

PeterUbers

think he meant to say "as also the amg m157 version was also affected ..."

PeterUbers

please link us to this info that details the changes made to latest versions of the m278

Sachant18

Sorry for delay,
see attached official doc from MB.

PeterUbers

doesn't speak to the new changes in m278 manufacturing to improve quality. Looks identical to the letter I received a year ago

do you have any documentation that speaks to the changes you state that were made to the m278 subsequent to these issues being identified?

are you presuming it has improved since 2016 is the last year that is covered in this campaign?

BlownV8

It's so rare for MB to change anything in production until the model line is complete. They seemingly would rather design a new engine than fix one in production. Also, I'd imagine there is liability to admitting any manufacturing defect. I doubt that you will find an official article that admits a defect or a change to fix said defect since it could be used in court against them at a later date. They are very careful to avoid admitting fault, taking responsibility for defects, and will fight recalls with every ounce of their being since it all costs money and they are in the business to make it and not give it back.