problems with 5.3 computer or hp tuners

[lssonoma]

I have a 2004 5.3 swapped into my s10 I hooked up hp tuners and removed the vats then wrote the tune. few days later i went diagnose why the fuel pump was not turning on/ why only 5 volts to the power wire and when trying to connect to hp tuners again either editor or scanner is tells me dectect protocol failed i have power from my obd and from the usb cord, all grounds are good and everything works fine when i plug it into my 2007 gmc sierra 1500. What would cause it to work then stop communicating just a few days later? the obd light on my mpvi2 has a steady flash to if that means anything.

[Nobleone]

Did you run the vehicle after writing the program without the Vats? Did the Fuel pump work at that time? Usually when you do not have a Fuel pump running and you cannot read the computer, the computer is locked. Have you tried to write the program again? I had this issue on one of mine I am working on. I had to rewrite the program and then all was good.

[lssonoma]

the fuel pump never turned on at all i think because of me having to wire in a new plug for it and maybe got the wires mixed up however I was still able to read the computer the first time and write the program now I cannot even read the computer to rewrite the program. but the relay for the fuel pump does click when i turn the key to on.

[Nobleone]

If the relay is not kicking on and you cannot read it, then it sounds like the PCM is locked. I had this happen on 2 of mine. I selected Write VIN and then selected Write calibration. It then corrected it so the PCM would function again.

[lssonoma]

ok definitely going to try this where is write VIN the only thing I have found is change VIN

[lssonoma]

that fixed it thanks!

[Nobleone]

Glad it worked for you!!!