Detect Protocal Failed

I am in the process of adding a\c to my 01 Silverado 2500hd pcm with a fbody style a\c system. My pcm originally was under OS#12208322. The fbody is OS#12212156, so I went in the tune repository and downloaded and used creidts for a 2002 Silverado 2500hd that has the same OS# for the fbody. I did a system segment swap from the fbody and the Silverdao 2500hd that has the same OS#'s. I went to rewrite my pcm that was orginally the 01 Silverado 2500 OS#12208322 to the 02 Silverado 2500hd OS#12212156. Everything was going fine as far as rewriting the file, my laptop said file complete and then the fuel pump came on and did not shut off like it should have. So after the stayed on constantly, I turned the ignition off. When I turn the ignition back on, the fuel pump stay on constantly and will not start. Also I tried to read the pcm again with the MPVI and it will not read but will just say Detect Protocal Failed. Is it possible you can tell me what the issue is?

Ticket has been submitted.

were you doing a write cal only when it failed/had the issue? Or were you doing a write entire?

Correct I was doing a write cal, or should I have done a write entire since I was changing to a different OS? Or did I brick this pcm?

I would try disconnecting the battery for a couple of minutes to try and reestablish comms, then write cal only again with the same file to see if you have any better results...with that said you are talking about a 20 year old ecm so its not completely uncommon for it to simply fail for no reason.

Last night I did disconnect the battery for over an hour, reconnected the battery turned on the ignition, tried to write cal and then it says Controller Unlocker: Timed Out and the same status, the fuel pump just constantly stays on.

Also, I would like to thank you for the help with this.

Writing a different OS does require a write entire.

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Originally Posted by 5FDP

Writing a different OS does require a write entire.

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Yeah I have a feeling something went wrong during the write entire process and the ecm is likely a doorstop now.

I didn't realize that I did not do a write entire until afterwards, total blunder on my part. At this point I think I will purchase another ecm.

i was doing the fuel pwm edit to mine... and basicly the same thing happened to me.. wrote entire,as soon as i powered the pcm backup it did the same thing,the fuel pump relay was buzzing,crank,no start.no comms to the pcm also.... i did everything i could, just a doorstop now... even tryed to reflash it back to stock with gm SPS then reedit it..... no joy,its a big silver brick....
and i still never figured out my fuel gauge problem,its supposed to go through the pcm,for some reason.... as soon as i get a pcm to replace it,i get to start over again,,,,the trans segment swap went well,,,, not the fuel stuff,,,, anyone know what to do to get the fuel gauge to work correctly?
2001 lm7,4l80.1999 gmt 400 dually came with 7.4 orignally.... now a big pile stuck on my lift,,,,HELP????