On occasion the navigation unit will not let me enter a new address. I have the car turned on, in park, and the screen has the address option grayed out. It will let me enter previous destinations but not new addresses.This has been occuring more frequently recently. If I drive for a half hour or so,the address then becomes available again (sometimes it does not). Has anyone had this experience before, and if so, is it fixable. It is not the disk, I have tried a new one with the same results.

 

Off the top of my head sounds like an intermittent error with the speed sensor circuitry. Once you're going more than 3MPH your Toyota Nanny won't let you input data. One thing you may wish to try is power, i.e. battery disconnection for about a minute which would allow components to reboot. You may loose radio and seat presets though and still not solve the issue.
A follow up question is: is the car keeping track of where it is located? It uses a combination of GPS data and wheel turns so if there is something going on with the speed sensor circuit you may see the car out of position from time to time...

 

Thanks for the reply. This happens when I'm in park, and when the car is moving most everything is grayed out. As far as positioning goes, no problem. The funny thing is that it is intermittent, sometimes it works and sometimes it doesn't. Something must be going bad, I would guess.

 

That's what I meant...for some reason your NAV system believes the car is still moving more than 3MPH even while in park...but only sometimes if I,understood you correctly.. And that seems to point towards the speed sensors. Intermittent errors are the worst. But if you are game, give disconnecting the battery a shot to reboot all the electronics.

 

Aren't previous destinations also grayed out if the NAV thought the car was moving?

 

No, Previous Destinations is still available.

 

Go figure, now the nav. is working properly. I'll wait until it acts up again and then I'll try disconnecting the battery. I'll let you know what happens.

 

I'm having this same problem. Sometimes everything is grayed out. Now, it always shows only Home and previous destination. Is there any way to do a "reset" or "reboot" without disconnecting the battery? I'm not afraid of that but was just wondering if there was a simpler way to do it. Thanks

 

Check out post #17 for the "soft" ECU reset.. https://www.clublexus.com/forums/sc-...highway-2.html

 

That Procedure is to recalibrate the ECU to for full throttle output, as a Lexus tech explained to me. I don't believe it will have any effect on the Nav computer.

JR

 

.....this issue has hit home with me also. Doesn't happen all the time,but sometimes when I try to enter a new destination, it will gray out the screen. Then I'm not able to enter anything. I know this is an old thread, but does anyone know anything about the "speed sensors" in the earlier post ???

 

I was fine for a while but now the error has reappeared. Initially everything was gone and now it is back to only Home and Previous. I have ejected and reinserted the DVD. I tried the accelerator reboot but that did nothing. I disconnected the battery for about a minute but that didn't work either although I did have to reset the clock. I'm going to disconnect the battery for a longer period of time and try that though I am not optimistic. Any other thoughts or suggestions would be greatly appreciated. Thanks

 

Disconnected battery for about 15 minutes. Now everything is grayed out. Very frustrating. Anyone have thoughts or suggestions? Thanks.

 

VVTiBob's posts about the speed sensors and/or associated circuitry makes sense. If you can get it to display your location while driving (the regular default mapping function) then if you see errors in your location you should strongly suspect problems in the sensors. If you can't get this display to work, then maybe hook up a code reader and see if any codes have been stored related to the speed sensors (I'm guessing here). The intermittent nature also may indicate problems with connections or shorts along the path starting with the sensors. Not an easy find. Not sure what the diagnostic procedure is for testing the speed sensors directly, checking the voltage the sensors are putting out at 0 mph compared to what they should be putting out at 0 mph is probably how Lexus recommends diagnosing potential speed sensor problems.

Disclaimer: I don't know what I'm talking about here - just guessing off the top of my head

Kelly

I'm guessing that the speed sensors we're talking about are at the transmission - looks like there are two of them. This parts listing from an after-market retail house implies 2 at transmission and 1 somewhere else????? Weird.

I'm thinking that failing ABS speed sensors would trigger codes and lights, so I suspect the transmission-located sensor(s?).

http://www.davesdiscountautoparts.co...0Relay&mode=PA

This seems like a shot in the dark:

http://www.ehow.com/how_7588719_rese...on-system.html