We were called to diagnose a Mercedes Benz W204 with the 271.860 engine, the client complaint was - no crank, no start, and delay in display of the check engine light in the cluster.
Just through the fact there was a delay in the MIL light, we knew the ME/ECU was not talking to the rest of the control units, wiring was checked and all checked out, the ME was opened and inspected internally and it was found that there were burns and damages beyond repair.
The client was informed and a replacement ME was purchased, we programmed and coded it.
The vehicle is back on the road, and yet another satisfied client.