Navigation ECU disassembly

This was an old note but because this problem with the Prius NAV system can still happen, I wanted to post that I just ran into this self-inflicted problem on a 2005 Prius and corrected it myself. The KEY to fixing this is to recognize that after removing and disassembling the NAV system, the little black switch in the earliest instructions has NOTHING TO DO WITH THE REAL FIX. The little black switch is in fact the EJECT button and has nothing to do with back up memory.

The fix requires the memory on the main board to be reset. This happens when power is removed - the battery on the 2005 versions of the assembly can be disconnected as described above by unhooking the ribbon cable temporarily. It is quite possible that on some systems, the battery is dead and that unplugging the unit will cause memory to be lost. In those cases, pressing the little black switch will "work", as will jumping up and down on one foot after disconnecting the power harness and connectors from the front of the NAV box.

I don't know about later model NAV units, e.g. 2007, and I haven't even looked to see where my 2011 NAV system unit is installed, but there should be some way to temporarily disable battery backup or reset memory in any system board. Unless the engineers who designed the newer systems are complete idiots..

 

This is an old thread but having just taken everything apart, I wanted to clarify a few things.

1) The switch labeled on here as reset is NOT. It is just a switch that tells main unit that the DVD loading door is open. The large ring shape object next to the black switch is the battery that is keeping the memory intact. It is soldered on. The only way to wipe the unit is to unplug the ribbon cable between the two cards. It has a friction fit. Lift up on the tabs beside the ribbon. The tabs will not pull free, just loosen. Then the ribbon will pull out.

2) You do not need to do anywhere near so much work to get the unit out.

a)Shove seat backward. Unplug the cables in the front
b)Shove seat forward, remove black protective plastic by pulling up the two round plastic "nails" on the top. They are flush with the surface. I recommend a small screwdriver and needle nose pliers or forceps. They are just a friction fit. The bottoms of these plastic "nails" are actually exposed on the side if you feel around. You may have to push on them from their points.
c) Use a ratchet with 8mm driver to remove the 4 bolts on the sides of the brackets that hold the sides of the GPS unit. Snap it free and pull it out.

That's it. You don't need to remove the bolts that hook the brackets to the floor like these instructions say.

 

Old thread back to life. I will need to try this, I have been guilty of playing with the loading settings, have done the unplugging with no success. I'll update with the outcome.

 

Successful! My navigation disk is now readable again. Greengecko's instructions were succinct but the visuals of vkykam made it easier.

I got into this mess because I was scanning through the override settings and decided to hit the loading button and pressed one of the unknown buttons. My current Nav issues is creating a successful Hybrid disc, I currently have a 11.1 disc, I tried adding a 4.2 loader and a 5.1 loader. They both work loading into the nav system, but I am unable to enter any addresses unless I am in region US1. I don't have this issue with just using the factory 11.1 disc and is only seen with the hybrid disc.

If you have any other suggestions on getting a hybrid disc working, please let me know.