Wow. Such an awesome detailed response! I will try your suggestions in the upcoming week. Thanks!

What you're describing is actually a fairly common complaint with the 2007-2009 Lexus ES navigation systems, and in many cases it is not a failure of the navigation system itself. A few things to check: "Automatic Transition" setting You already found the correct setting. When working properly, setting it to OFF should prevent the system from automatically returning to the map screen after a short timeout. If it is already OFF and the system still returns to the map, then either: another setting is overriding it, the software has glitched, or the navigation ECU is behaving abnormally. Route Guidance Active Make sure no destination is active. Even if "Automatic Transition" is OFF, the system may jump back to the map screen during active guidance to display upcoming turns. Cancel any destination completely and see if the behavior changes. Voice Guidance Prompts Some owners have reported that the system returns to the map after voice guidance events or traffic-related navigation events. Again, this would be more noticeable when a route is active. System Reboot These Denso-built Lexus navigation units occasionally develop odd software behavior. Disconnecting the vehicle battery for several minutes (if radio presets and other settings can be reset) or pulling the navigation/radio fuse can sometimes clear strange behavior. Hidden Touch-Screen Fault This is less common, but I've seen touchscreen panels develop "phantom touches." If the MAP hard key or a touchscreen area associated with navigation is intermittently sending inputs, the unit can appear to force its way back to the navigation screen. Watch whether it returns at perfectly regular intervals (software issue) or randomly (possible hardware issue). Aging Navigation ECU By 2009 these units are now quite old. Internal memory corruption in the navigation computer or DVD drive can cause unusual menu behavior even when navigation still otherwise works. A simple testWith the car parked: Start the vehicle. Verify Automatic Transition = OFF. Cancel all destinations. Select the Audio screen. Leave the car sitting for 10-15 minutes. If it still jumps back to the map screen with no route active, that strongly suggests a software or hardware issue rather than a setting you've overlooked. My suspicion is that you've already found the correct setting, and the fact that it was already OFF points away from user error and toward either: an active guidance condition, a software glitch in the navigation ECU, or a failing touchscreen/navigation unit. One question: when it returns to the navigation screen, does it happen after roughly the same amount of time every time (for example, 15-30 seconds), or does it seem completely random? That detail would help narrow down whether you're looking at a software behavior or a hardware fault.

We all have them every so often. 😏

Purchased this ES350 a year ago and have been annoyed to no end that the Nav system always seems to return to the navigation screen from either the audio or the climate screen. Today I searched through the Navigation owner's manual and found the setting (Info button, "screen setting", then set "Automatic transition..." to OFF). The setting was already set to OFF. Is this a known issue or have I missed another setting? I would be pleased if the navigation screen never appeared again.

Thanks! The weather has finally cooled down some here, and I haven't noticed this since, so I suspect it is temperature-related.