Okay new here, but not new to 6.0s
I have a no crank no start. Last harvest we had this issue, thought it was the starter so I changed it in the field, turns out that wasn't it, so we ended up using that passenger side wire to start it once in a while and it eventually got better, and we didn't need to use it. (needed the truck to get through harvest) since then it hasn't done it, until this year. Dad took the truck to the city and on his way back had a caliper blow up, so he kept adding brake fluid to get it home so we could fix it. he spilled some brake fluid around the tank, got home, shut the truck off, next morning no crank at the key, tried the passenger wire, and it cranks great but wont fire.So we checked all the fuses under the dash, and nothing blown. He took apart the connectors under the brake reservoir and cleaned them out with electrical contact cleaner still nothing.
Once in a while before this, the truck would stutter and run rough for a few seconds. We did on the injectors in the fall of 2018.

We do have a bad mice problem havent found any bare wires yet, but I wouldnt rule out a mouse doing something like that, had it happen before on the alternator wires.

So I have no crank no start with the key and with the passenger wire it wont fire.
No injector buzzing either
FICM voltage on pin 4 is 48.5
Can feel the 302 relay clicking when I try the key, swapped that relay too
Lights on the dash are all coming on
When I plug my ELM 327 reader in, it connects but says it cannot connect to the ECU, works fine with my 6.4L though

Is there anything on the PCM that I can check?
What is a typical procedure for this type of problem? I am familiar with some lingo but not the locations of some of these things.

Sorry I know this has been asked a billion times, but I am having trouble weeding through all the threads and understanding some terms and procedures. Not easy to find someone with same problems.

 

Did you check all the fuses? I'm not good with electrical issues, but don't see how spilling brake fluid around the reservoir could damage anything below it. Maybe if he spilled it in the fuse box above and to the right of the reservoir. I believe there are some fuses that control starting and ignition.

 

I have received more info on the drive home before it quit. about 20 minutes in on the 3 hour drive back, he had the gauges all quit, then the truck actually stalled on him. He was able to start it again and finished the drive home, then he shut it off and it hasn't started since. I am really leaning towards a bad PCM because there isnt one single bad fuse in this truck. But I have no idea how to even check it, when I put my ELM 327 bluetooth code reader in, it says cannot connect to the ECU, which would be the PCM ? He really didn't spill much brake fluid, and it wasnt over anything like fuses, just a few connectors under the tank there. I think its purely coincidental it wont start now, like I said the truck wouldnt start with the key the odd time in the last year, and would run rough for a few seconds once in a while too. I have no injector pre cycle noise at all either. FICM tested 48.5, which is spec.