so long story short i’ve rebuilt my truck from the frame up, it’s ready to start but it won’t even make a noise when turning the key, i got it to show C-Codes, it’s showing AA and AB which is PCM and TCM messages not received, it there anything i have to check or do to make this go away ANY help is greatly appreciated

 

What year is your truck? Engine? Trans?

 

2002,
4.7
46re

im fairly certain it’s the PCM and ECM grounds , and the 2 engine grounds on the passenger side that’s causing my problems, but if not then idk what

 

PCM has nothing to do with the cranking circuit. It's all about the relay. I don't know if the relay's in yours are removable..... but, Trans in park, ignition in start position, (a second warm body makes this a LOT easier....) you should see 12 volts on pin 85 of the relay socket, and pin 86 should go to ground. Either being missing will result in a no crank condition.

Are you sure that a 46RE??? and not the 45RFE??

 

i’m not too sure on the trans, that’s what i thought it was but also i ran into way bigger problems, i added 2 grounds, 1 for the PCM 1 for the ECM checked all motor grounds and some other computer grounds, all good, but after i turned the key again and got the terrifying “no bus” message, and i have no idea what causing it or where to start, or even fully know what that means, i called the dealership and they said “i don’t even know what that means” so no help there

 

The dealership is pullin' your chain. They know exactly what it means. At least, the service department should.

I would start be removing your grounds, on at a time, and see if things come back. I suspect you are grounding something you shouldn't.