I can't seem to figure it out. The only part of manual that I can locate is the chapter 19.1-19.x troubleshooting electrical components. It refers to chapter 18.30 for one of the mentioned options. Then it goes on to explain the toggling of codes and describes how to interpret the codes. Stores max of 10 codes. First the code, then the time since fault occurred follows in chronological order starting with the most recent I believe. I tried holding horn when turning KOEO (Key On Eng. Off) to trigger menu as it was a Toyota method I found, maybe for a did year or something. I almost forgot about the screen is basic so maybe the horn method is for deluxe. Also tried holding tilt lever button/switch when turning KOEO, nada....thanks for any help:-)