Before diving into the manual, it’s important to know what makes this engine tick. The OM646 was an evolution of the OM611. It introduced:
Operating at up to 1,600 bar for better fuel atomization. Mercedes Workshop Manual Om646 Engine
Diesel leaking past the copper injector seals leads to "black death" (carbon buildup). The manual provides: Before diving into the manual, it’s important to
Underboost (check vacuum lines to the turbo actuator). P2047: Injector circuit malfunction. Before diving into the manual