Only runs one way

Sorry for the delay but these questions are put in que from oldest to newest according to the last update. So unfortunately when you updated it, it put it back at the bottom of the que.

Just to be sure we are talking about the same thing. When you say the only way it will run is with the shunt out, you mean the wire that is used to display the charge state of the vehicle?

I attached a description below if you can review that and let us know. Then if you don't mind getting a video of this starting and running with it out that would help us figure out what else this could be.

Thanks

So if the engine only starts with this out then I suspect that wire has excessive resistance in it. I don't see how that is preventing the starter from engaging so you are correct that this is an odd one, but the PCM must be failing to ground the starter relay when the shunt is pulling the meter down. These systems are tied pretty closely together but I have never seen this so it will be a new one on me.

Have you tested the resistance of the wire?