ive got a 78 monte carlo ive swapped a 5.3 in, im using a 2001 model truck fuse box and wiring harness from a 2003 and 2004 zo6 computer, ive re pinned the c2 connector in the fuse box to match the fuse box. i can read the computer once i get pass the aggravating security fail but when i go to write a calibration it fails and says "mode 1 check failed" or something similar...any ideas?

 

mode 1 erase failed mode 1 check failed is what it says, anyone?

 

I have never run into this. I think you should bug support@
about the error messages. You might also consider trying a
bench harness (junkyard wireball from a vehicle matching
the PCM donor) as a way to determine whether it's a problem
with the swap wiring (other than tedious / error prone wire-
poking).

 

there is so little harness that its practically a bench harness and i just about have all the harness out of the car, its killing me. ive heard it could be from battery voltage or wiring and both seem to be right, to make this harness work i had to re pin fuse box connector c2 from a 2003 to match that of a 2001 so that the fuse box i used from a 01 truck would work but i feel pretty confident i have it right

 

Something is not right with PCM power supply.
Check if all +12V feeds and ground are properly hooked. Check battery charge, it must have at least 12.2 V

 

I've got 12.8 volts on connector c2 pins e2 and f2 per 2001 truck fuse box pin out since I'm using that fuse box and according to lt1wiring . com those are the ones that power the pcm. And the rest of the wiring to the pcm looks good. It is really weird that I read entire and scan the pcm but can't write.

 

Write failures are ussualy caused by low voltage to the PCM or bad grunds. It's not the same as read entire, because erasing and flashing a memory chip needs good voltage.

I would stop messing with the PCM because you are going to brick it.
Test it in a 2003 car, if you can flash it there then the harness is the problem.

 

I'm going to find a pin out for a 2004 zo6 ecu and see if the harness is ran correctly just in case the pin out on lt1wiring is different