I was driving and I started to lose power. I pulled over and the engine died. It would not restart. I have about 1/4 tank of gas according to the gauge. I had it towed home. I have an SDS unit. I plugged it in and don't see any faults or codes.

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.