DD15 crazy sensor bank problem

2014 Cascadia with DD15

I am having one hell of an electrical problem with my sensors. Check engine light comes on and off, sometimes the engine stop light comes on and forces me to shut down because of "engine timing failure".

First off, here's my wonderful collection of SPNs:

SPN 5927 FMI 2 coolant sensors (this one is the most common, keeps coming on and off even when everything is running normal. The coolant temp gauge keeps displaying correct temperature. This one also started first, a few days ago, before all the other ones joined in yesterday.)

SPN 3510 FMI 4 ECM 5V sensor supply bank 2 circuit failed low

SPN 100 FMI 4 oil pressure sensor (when this one goes as I'm going down the road, the oil pressure gauge drops to zero and I know the real fun is about to begin soon)

SPN 723 FMI 8 camshaft position sensor time out
SPN 723 FMI 11 camshaft position sensor failure (when these last two come to play, that's when the shut down is forced. But if I keep pushing the override button, it keeps running with no noticeable charge in performance.)

SPN 3226 FMI 20 NOX sensor in emissions (might be unrelated)

These errors are frequentish but inermittent. Sometimes I can drive for hours with just the coolant sensor check engine light blinking on and off. Sometimes all of them will happen simultaneously, but when I turn the truck on a few hours later everything is clear. Sometimes it's the other way around - I park the truck healthy, but when I start it all the boys are back - and I have to try starting a few times before it will even drop the camshaft error and let me run, and then the errors drop off one by one in a few miles. So basically, it does not seem directly related to engine being hot or cold.

We are under a cross country load, so we are trying to make it to LA. Tried to take it to a shop in Canton OH, but of course just then the problem wasn't happening and we couldn't replicate it. The shop looked at my wiring harness and in their own words "couldn't find anything obviously evil".

So... any idea how to diagnose this? Any common trouble spots in the harness, etc, that could cause this combination? Also, can one bad/shorted sensor confuse the circuit into this chain reaction? Like, maybe the coolant sensor? Or are they pretty isolated?

Any advice appreciated. It's hard to go to shops with this when it doesn't happen on demand.

 

That... that is kind of a last resort thing. $5000 3 day job because of one bad wire is something I would prefer to avoid.

 

I thought about that, but the thing is, it happens on dry days as well as wet days. Rain and water don't seem to affect it one way or the other.

 

Wow, yuck. I will definitely pop off that connector and take a look. Thanks for the advice.

 

Yes, I had a oil leak that was going oil all over the engine harness wires underneath the engine. Replaced the engine harness and fixed the leak. About $2,500 for the new harness, new air compressor ( the thing that was leaking) and labor. Not cheap.