Mercedes R Klasse Diesel ECU Issue

Oh man, ECU problems are the worst! I had something similar happen with my R Klasse, diesel too. Engine performance just tanked, and the error codes were all over the place. Did you try anything before suspecting the main relay? Like a system reset perhaps?

A system reset was performed, but the fault reoccurred. I suspect the relay because of the intermittent nature of the fault. Do you have any specific details on your issue and how it was resolved?

Yeah, that sounds about right. Mine was acting up randomly too, then just completely died. I ended up taking it to a workshop, and they confirmed it was the ECU. I'd suggest doing the same if you haven't already, before you go chasing other ghosts.

Confirmed. The main relay was indeed the issue. Replacement fixed the problem. Thank you for the advice.