Well either ecu is done or your have a broken wire. Checked to make sure all those sensors are plugged in ? Is it possible that there's an inline connector between those sensors and the ecu that might be loose? Might be making this up but I thought I read that limp mode somehow locks out 5 and 6 gear, or did I just make that up? I feel like I'm obsessing over this 5 volt reference too much.but the last code is a 5 volt sensor reference code. Man would I love to look at your car to prove myself right.