I recently purchased a 2001 sc 430. A well maintained vehicle with few problems. I have two distinct problems with the nav system. The first has to do with the open/close mechanism for the nav cover. Door works perfectly as long as the tilt position is not in the fully tilted mode. If it is in the latter mode the door will sometimes hung up closed or open. I believe this is due to bad contacts in the tilt position switch. I have previously disassembled the nav unit and cleaned this switch (not a simple operation!), but I suspect there are still residual contact problems. I can do this cleaning again if I get enthused. After the first cleaning things worked much better. The second problem is more mysterious. The nav seems to work perfectly for extended periods of time but then portions of the on screen map start to go blank and finally the only thing visible on the nav screen is the symbol for the car position. When this failure happens you can stop the car, turn off the engine, start it back up and the nav starts working perfectly. The car has an after-market nav upgrade dvd sold by a company in Las Vegas (for $25). Can this be the problem? My understanding is that this disc also upgrades the nav software, so you cannot simply re-load the original factory dvd. I don't remember seeing this nav problem with the original dvd in the car. but I was not using the nav system much at this time, so whether the original system had this failure is unknown. Anyone else with an aftermarket dvd upgrade disc see this see this nav problem?

 

Moved to the appropriate Lexus SC430 sub-forum : )

 

Why are you still using the NAV ? It’s worthless . The only thing it’s good for is back up cam. Use the phone for navigation, much better with live traffic and more. My two cents.

 

Or better yet get a new head unit with CarPlay hook your phone to it and throw phone in the glove box. Get backup cam, nav off of phone, texts, phone calls etc. And that's my 2 cents...