Duramax LMM ECM problems

I am still very new to EFI Live and using the AutoCal set up. I have a 2008 Chevrolet 2500HD Duramax. I bought it a year and a half ago. At the time it only had 56k miles on it. Now I have 91k miles on it. I bought my EFI Live AutoCal set up with the DPS5 switch and 5 custom tunes from ATP trucks July of last year. Idaho Rob did all of the tuning. Along with this I also bought and installed a S&B cold air intake and exhaust to delete the DPF, catalytic converter and muffler. It is just straight 4" pipe from the down pipe back.

I installed everything last August, never had a problem, and was very happy with my $1600 purchase. I work pipeline so I travel all over the country to make a living. I left my home in north Louisiana May 10th of this year towing my fifth wheel trailer up to North Carolina. A few weeks previous to this the 40 amp j-case starter fuse blew on my truck and it would not crank. I replaced the 40 amp fuse and it cranked right up. No more problems. Two days after I got to North Carolina I was going to run up to the store and my truck would not start. I ran the diagnostics with my Edge Insight CTS and it did not find anything. I checked the fuse again and it was good. I then plugged in my AutoCal to see if it might find something in the diagnostics my Edge CTS did not. At first it was working fine and I could not find any DTC's.

At this point I began researching possible causes on various Duramax forums. I attempted to re-flash my custom tunes onto the ECM because I read that a lot of the time just re-flashing the ECM will fix this problem. This time however I got a AutoCal error code saying it could not communicate with the ECM. I tried a few more things and assumed my ECM had bricked. I took my truck to the local dealership and they replaced the ECM. I reloaded my custom tunes without a problem and had no issues over the next week. Then just as I was about to leave work I went to start my truck and it all happened again. And again I assumed that it was a bad ECM that was installed. Since the truck is over 5 years old the dealership could only install refurbished ECM's due to new ECM's for my truck were no longer manufactured.

I took my truck back to the dealership and they had it another week replacing the ECM again. I picked my truck up that Friday around noon and drove it all afternoon and evening without a problem. I did not reload the tunes though because a I did not have the money to purchase another license at the time. I got up the next morning and I was worried my truck was not going to start so I checked it. Sure enough it was doing the same thing again. I had it towed back to the dealership and I just got it back yesterday evening.

All evening I continuously checked it to make sure it was going to crank. After the dealership kept telling me over and over again one excuse after another I was gun shy about it. The dealership had replaced the ECM, the BCM, the security control module, the brake controller "There was nothing wrong with the brake controller by the way" then they re-keyed the ignition and applied dielectric grease to all of the connections and made sure they were securely seated. They were supposed to replace the brake switch but even after having my truck 3 separate times they never did.

Since my truck seemed to finally be fixed I went ahead and purchased another license so I could re-tune my truck again. I flashed in the tunes back onto the ECM and everything worked fine all day. Then I went to leave work for the day, and guess what? The same exact thing happened again.

I began researching the internet because I did not want to pay for another tow bill or a license. Plus it did not help that I was broke down in a very sketchy area. I tried everything I could find. Then I found the tutorial on hooking up my autocal and laptop to the OBD and perform a full flash on the ECM. It took me a little while to do it because I kept trying to get the autocal to just read the ECM using my laptop and it would not do it. I then disconnected both batteries for 30 minutes, checked the lighter fuse, and pulled the radio fuse. I hooked the batteries back up and my truck still would not start. I then did a full flash of the ECM and returned it to the GM stock tune and it ranked right up.

So is it possible my custom tunes have corrupted and caused this? Or is there another possibility? Please help I want my tunes back on my truck but I also want it to crank up when I need it without a issue. Any advice or suggestions are greatly appreciated.