I have seen some weird problems lately. Sometimes in the middle of programming I will see what I think says there is a checksum error...I can't be sure because it flashes fast and keeps going. One time I had the error come up and the flash writer cam out of high speed mode and switched to low speed mode. How concerned should I be when this happens? When I get these error I load again until I don't see any errors during the upload. Yes, the cable is in all the way, and yes there is sufficient power to the PCM. Weird stuff.