06 ML500 Died Won't Start No Codes How to Troubleshoot?



Please could someone advise on a troubleshooting protocol for this situation? If anyone has systematic set of procedures or tests, I would love to to learn to work through this type of problem. I initially guessed a bad cam position sensor, but I would have expected a code for that. Also, I can see that the fuel filter maybe bad. But, I don't want to randomly change parts.
Any advice gratefully received.


