Found the way to override Navigation without cutting wires.

Man, I wish I would have read this thread before I too got brave.

I got here by clicking on the Load Application screen. The first US option seemed to do nothing, so I tried the second one just to see what it did, and now I'm stuck at the same point.

What's worse is that at 40.6k miles, I'm out of warranty, and can't blame it on some sort of glitch.

If you find out an easy fix, please advise.

I'm hoping it's just a matter of which item it loads from the disc, and not flashing the NAV memory w/ a new app (or waiting to do so).

 

What's worse is that I've lost the ability to use bluetooth as well.

 

Spent some time at techinfo.toyota.com and that search turned up nothing.

Also looked at the NAV DVD again - my guess is that it's not finding what it wants in LOADING.KWI - I was hoping it would be as simple as renaming an image file, and burning a temp DVD.

 

Here's what I see now instead of a map.

Phone buttons don't work on wheel, neither does voice. Phone screens somewhat accessible from info screen, however buttons are not active and bluetooth connection is no longer established.

 

I've tried disconnecting the N2 harness which provides the power (one closest to the driver's door on LHD cars) for about 30 seconds, no luck.

bretray mentioned that he noted a battery w/ a wire soldered to it. I'm guessing this will need to be disconnected in order to truly clear it. Unfortunately this probably means I'll lose my stored points, etc.

As for bluetooth, there may be hope - I found a place to do a memory clear (in an effort to fix this) wihch may explain why that's not working - simply re-pairing my phone to the car may solve that.

New Toyota manual disclosure - Warning, curiosity killed the NAV.

 

Edited for clarity...
FIXED IT

Howto to follow.

WARNING: Attempt this at your own risk!!! I take no responsibility for misinterpretation of these instructions which may lead to permanent damage to your NAV ECU or yourself. However, since you got this far in "breaking" your NAV, you're probably brave enough to fix it too!

Steps:

Pull NAV ECU:

• Remove rear plastic cover by pulling plastic retaining clips/pins. I found two flathead screwdrivers helped with this.
• Remove 4 8mm/philips screws, 2 on each side retaining ECU.
• Remove 4 harness connectors at front of driver's seat.
• You'll need to spread bracket just a tad in order to dislodge the ECU from the bracket.
  • 
    
    Open NAV ECU, perform "fix":
    • Remove 8 screws from the bottom of the ECU.
    • Cover is held in place by 1 tab on each side that fits around a small bump on the top cover. Using a small flathead screwdriver, spread the cover at the bump. The ECU cover should then tilt up and come right off.
    • With the plugs at the front, the left board is the NAV logic, and the right appears to be the AVC-LAN interface and power supply. There is a ribbon cable separating the two. These boards should lift right out, as the cover screws are holding them in place.
    • At whichever location is easiest, lift the retaining clip at one end of the ribbon cable connecting the power supply board to the "logic" board, then gently pull the ribbon cable free. This effectively disconnects the battery backup from the ECU.
    • I also spotted a black momentary switch on the power supply board. This may also be a reset/backup power interrupt, however being a multi-layer board, I couldn't easily follow the traces to double-check. For safe measure, I press and held this for a few seconds as well.
    • Re-insert the ribbon cable, ensuring that it's aligned correctly. Push the retaining clip back down to secure the cable.
    • Replace the boards, ensuring that the boards fit onto the alignment tabs. The power supply board was a bit tricky here.
    • Replace the cover. I found that securing the screws over the power supply board first helped to keep it aligned as mine wanted to pop out of place.
    • Replace the ECU, reversing the steps of removal.
    • Power on. You'll see on the NAV screen: Loading application, do not power off.
    • I then saw the "Agree" screen. Success!
      • 
        
        You'll need to restore all of your map points, but that's a minor inconvenience compared to the cost of a new NAV unit or a dealer visit. Hope this helps anyone else who was unfortunate enough to see what "loading" did.
        
        Sorry for lack of pics, perhaps the next person to attempt this fix could photo-document this.
        
        *mod edit: See this thread for pictures of the process:
        http://priuschat.com/index.php?showtopic=33878&hl=

 

Were your BT numbers and pairing preserved or did you have to redo all that too?

 

Oh, and Well Done!!

 

Honestly, because I went through and did a memory clear elsewhere (can't remember exactly where), I'm not sure if that action cleared the BT pairing and numbers or if the NAV reset cleared it. I'm unsure as because even though the NAV was horked for a bit, I was able to (via the info button) get to the telephone screen. The data was gone at that time.

Perhaps the next person who trys this could verify.

 

I did have to reset the region, timezone, as well as all of my nav preferences (speeds, etc.)

I am not willing to try any other loads for now, since it was a pretty involved process. Perhaps in the future I can experiment further to see if we gain/lose any functionality. However now that it's a "documented" fix, perhaps others may be more adventureous.

I suppose next time I try I could also see if the momentary switch is a "reset" button.