Everyone runs there same ECU from previous races as they r marked and given back to the specific car during tech at next race
that may be what you read on the forums, or have heard. but i have been there with many teams that clearly had different issues from Parker to World Championship. they may be THEIR original ECU but the ECUs are getting reflashed to the stock latest flash from polaris after they are confiscated. you may get YOUR ecu back but that dont mean its 100% as perfect and proper as you wished, nor does it mean your machine will run the same as it did the last race. we proved that to be true with Burnetts ecu not working properly after tech at World Championship. only found out friday night out testing. we were allowed to swap ECUs with PEAK powersports for a brand new OEM ecu as they supply everyone else and the 4wd worked. the guys at PEAK also installed Marcs ecu supplied to him on their daily driver 4 seater and confirmed it was the ECU was bad because the 4wd that was working, did not work after they installed Marcs ECU in their 4 seat backup car.
So just because you assume you are getting your ECU back at tech, dont mean you actually get YOUR ecu back you had the last race. I know for a fact Johnny wouldnt have loaded his rig on the trailer Thursday morning to head to vegas if his 4wd wasnt working. my bet is that his newly supplied ECU at tech had a 4wd glitch just like the one Marc was supplied before WC. I am no mind reader, and i clearly wasnt there, but i can tell you from experience that the ECUs are getting reflashed with the "latest greatest" flash directly from polaris after they were pulled. clearly there are some glitches in this system and it seems that this issue is what cost johnny a DNF.