Hello Everyone: I'm new to the forum and I have a new problem with my nav on 2003 gx 470. Today, the NAV starting displaying unable to read data. Even though it has never failed ion cold weather, I thought it was cold related. After warming the car the problem persists. I located the DVD player under the seat. Ejected the DVD... seems clean but cleaned it and reinserted it. No change. I've never upgraded and would like to but I'm not sure that the problem is only the DVD. Is there a way to reset it and has anyone experienced sudden failure like this?