Originally Posted by Harold57

That's great news RDF21. Glad to hear that you got the problem resolved.

From your write-up, it sounds like you believe that the 3V Lithium battery is rechargeable. I don't suppose that you got the part number off of the battery did you? I suspect that it is not rechargeable but could be wrong. If it is not rechargeable, you may have damaged your battery and should consider replacing it.

Originally Posted by RDF21

I didn't happen to get the part number. I did get the impression from the thread below (see post #4) that the battery is rechargeable. A couple of people had success with this method and none of them reported back that they did damage to the battery. That is by no means definitive, however I should know within a couple of days if the settings are being retained or not. I also have other reason to believe it is rechargeable in that during my drain test, I reconnected the unit when the battery had drained to 1.75v. The NAV ECU did not reset at this level of drainage and by the time I re-disconnected the ECU the battery was back to 2.75v and I had to begin the draining process all over again.

If the ribbon disconnection is an option, it is definitely preferable to draining the battery. It is much faster and puts the battery at no risk of damage. This option is available for GEN 4 versions of the NAV ECU but I don't know about others. If anyone needs to attempt this, I advise patience and caution while disassembling and re-assembling the cable. Be careful to insert everything firmly and securely and use electrostatic paper to separate components.

https://www.clublexus.com/forums/hyb...t-map-dvd.html

PS
The battery on this model is soldered in and is not easily replaced unless you are handy with a soldering iron.

Originally Posted by mrblister

I believe the tab that is on the lithium battery was electronically soldered [ not with heating the battery up ] The lithium batteries will explode if you heat them with a soldering gun very dangerous to attempt. I don't know if you order the exact part if it will come with the tab already attached to the battery.

Originally Posted by texsexlex

...if what ShawnOk stated doesn't work, then your unit may be going out,I had this issue about 2 yrs into owning my Sc. At that time, there wasn't any units available on ebay & the dealership wanted $1500,if I recall correctly. I did a google search & found a company in New York state that actually refurbished Lexus nav systems for the dealerships. I think I paid about $400 & all I had to do was remove the unit,send it to them & they repaired it. The whole process & turn around took about 10 days. If your nav system is a Gen2/3, I would look into upgrading to a Gen4, this way current year disc would still be available to you

Originally Posted by Bgw70

Here is the nav override procedure. It is a different unit but should work the same for gen 2/3 units.
https://youtu.be/qNkCB6XUq04

Originally Posted by Bgw70

Here is the nav override procedure. It is a different unit but should work the same for gen 2/3 units.
https://youtu.be/qNkCB6XUq04

Originally Posted by GmanSC

Serriously, you do not want to override the Nav. My friend was nearly got killed when he inputed the destination to the Garmin GPS while the car was moving. He went thru the red light and was T-boned by onother car. Don't do it, guys.

Originally Posted by RDF21

Thank you very much for taking the time to reply and recount your experience. I am pleased to report I was successful!

The battery drain test did not work for me. Mainly because the LED I had on hand took 3 days to get the battery down to 1.5V from an initial state of 2.75. I wasn't thrilled with this approach anyway as I was worried about draining a battery of this age to abnormally low levels and having problems recharging or maintaining a charge afterwards. I eventually abandoned this method when I found that some users had success disconnecting the ribbon cable. Initially I had looked at this and thought the ribbon cable was soldered in and not disconnectable. I had a closer look with a 10x jewelers loop and was able to flick one side of the ribbon retention bracket up with my fingernail and then the other. The ribbon popped out after that. I left it disconnected for a few minutes and then reassembled everything. When I put the unit back in the trunk (without a DVD installed), I got the "Please insert correct DVD" message that I had been receiving previously. At this point I thought I had failed, however, having everything apart already anyway, I inserted the original disc back in and it began to load much to my surprise and happiness. The unit is now working!

Things to note. It appears this method works as the chip that retains the memory and settings is on the other board without the 3V lithium battery. Severing this connection finally drained the memory and the bad setting or condition preventing the original disc from loading. This also had the effect of clearing all of my memory and presets. Something I am happy to deal with rather than buying a new or pre-owned unit and having the same situation anyway.

I've included a couple of photos, especially of what the ribbon cable looks like when it is free. I wasn't able to find any images of the ribbon cable disconnected in the forums, so hopefully this post
and images will help the next unsuspecting soul.

I will add any other relevant thoughts if I think of any.

My sincere thanks and appreciation to you, Club Lexus and the ingenuity of the collective.

RDF