[Stapleton42]

One time I randomly lost engine power while going down the road. Instant shutoff with no explanation. Turned out to be the 12v switched power wire feeding the DDEC ecu broke off right at the pin. If you or someone else in this situation can't find an obvious reason for an issue I would check the plug at the ecu for broken or almost broken wires.

[CaptainGizmo]

Well…this is an old resurrected thread. But now that I’ve read and gotten sucked into it…LOL…I’m having PTS all over again.

This exact thing happened to me as I was driving my 2015 home…literally within hours of purchasing it!!

It was pouring rain, I hit a dip at freeway speed, and everything went dead. Pulled under an overpass and did a full shutdown and…luckily…I got it all restarted.

Thankfully, my next stop was Newell service where I got my first lesson on the MERGE RELAY (used to be called a klaxon) in the load center. I know my 2015 is set up differently than yours, HOWEVER, my experience may translate to others.

Those merge relays burn from heat, then become weak. The top of one was brown from heat discoloration! There were a set of relays and both were replaced with higher capacity (amp) versions. One tech suggested replacing them every year!

[bikestuff]

I am not sure of what you circled...but the square "circle" looks like an automatic breaker to me. These devices act like fuses...but will reset themselves. Can you check for voltage on both pins of the square device. Also...the tube fuses look a little suspect just to the right of the square device.

I just noticed that this was an old thread.

I wonder what the final resolution was???

[Newell 381]

Thank you all for your input and replies. I ended up sending the ECM to a specialist to analyze it. The ECM was actually functioning properly, other than a failing memory module (which would not effect the no-start condition). After following the advice of things to check by the ECM specialist, I discovered a failed 12V circuit breaker that supplied power to 1 of 2 legs of power to the ECM in the engine bay. After replacing it, bus fired right up.

[Richard]

In my own debacle with DDEC computers, a sage DD tech taught me a simple shortcut.

When you turn the key to on, before twisting all the way to start, the check engine and shutdown engine light should illuminate and then go off. If they do NOT illuminate, you do not have power to the DDEC or it’s completely dead.

[Newell 381]

That’s good advice. The crazy thing about my situation was that with the ECM having 2 legs of 12V supply, only part of the ECM had power. The STOP and WARN lights WOULD illuminate but due to the failing memory module (the module that records stored and active codes) it wasn’t able to record that there was a partial power failure. Fortunately, the ECM tech gave my ECM a clean bill of health and now I have updated memory modules. I also bought a spare supply of Blue Sea circuit breakers in case more fail.

[Jack Houpe]

In my own debacle with DDEC computers, a sage DD tech taught me a simple shortcut.

When you turn the key to on, before twisting all the way to start, the check engine and shutdown engine light should illuminate and then go off. If they do NOT illuminate, you do not have power to the DDEC or it’s completely dead.

This is good information to know!