Can't Unlock Nuvi

My only thoughts prior to your returning to your Secure Location is to give it a long battery charge (overnight on a USB computer cable with the computer set not to go to sleep or a long charge via cigarette lighter plug from a plug that doesn't go off with the ignition key) or to give Garmin CS a call and see if they can do anything to it via an internetted nuvi-computer connection.

Nuvi 855s are known for phantom battery discharges so a weak battery is my first guess--and the easiest to remedy.

That's not a bad idea, the unit is actually connected (and hopefully charging, but who knows) via the USB cable.

The only thing new is that it is prompting me for a PIN while the USB is connected, although it still does not respond to pressing the numbers.

I am sure the battery is charging from the USB even without the PIN being entered. The problem could be that the USB is extremely slow. It could take 6 hours to charge the battery fully and the PC can't go to sleep in that time.

If you are away from home this whole problem could have been caused by charging on the USB. Find a plug-in charger for a cell phone that has a mini-USB connector. This will supply more current at the proper voltage for the nuvi, but will still take 3 or 4 hours to charge fully.

dobs108

Ok, the battery *should* be charged, but my problem does not seem related to the battery charge level. I have the same behavior whether or not I have the battery installed. I can try calling Garmin although my unit is beyond its warranty....

I will be near my secure location sometime next week, but was hoping to use the GPS during the road trip back there....

http://www.mydigitallife.info/how-to-reset-garmin-nuvi-gps-d...

the last paragraph says:
"Unfortunately, even if you perform master reset on Garmin GPS unit, it does not reset Garmin Lock security feature, which password-protect most Garmin electronic devices to deter theft. If you forget the PIN or password unlock code to unlock the Garmin unit, the best solution is to bring it to Garmin to get unlocked. “Secure Location” does not unlock a locked Garmin unit either as it’s only a temporary fix as when it’s turn on outside the security location, the device is locked again.
"

My Nuvi 660 has always prompted me for the PIN when I connect it to my PC via USB. It's normal operation.

Several months ago, my touch screen went bad. The 1st indication was no response when I tried to enter my pin - no audible beeps and no *s were displayed. I drove to my secret location which unlocked the unit.

From the main screen, I got no response to anywhere I touched on the screen. That confirmed the touchpad had gone bad.

I experienced it one time. I had to travel to my secure location to unlock it and did a screen calibration which fixed it.

I don't know why I lost my screen calibration but I did. I really haven't used Garmin Lock since. Nor have I had to re-calibrate the screen again.

So after a few weeks of experimenting here is an update. I returned to the secure location and it did not unlock. So I've been trying other things:

1.) I've been successful in semi-reliably getting the GPS to mount as a drive after using the Pre Boot Mode while connected to a computer to unlock the Garmin Lock. This only works with a certain order of events that I found via trial/error. This never works if I have an SD card, but I can access the GPS files.

2.) I've tried to update via the Garmin support website (it says everything ok/ up to date.

3.) I've tried to update the firmware using webupdate, with no change. (Unit already had 4.70 but thought refreshing it could help).

4.) I reinstalled the boot load/firmware via updater.exe and the appropriate .rgn file. This was successful but did not solve the problem. Is there a safe mode rgn file for recovering after file problems?

5.) I can get the unit unlocked (using pre-boot mode) while using external non-computer USB power. However it hangs on "Loading Maps."

6.) If I start the GPS normally, I still cannot enter anything at the PIN screen.

7.) So it seems that getting past the "Loading Maps" screen is the best bet. I've heard that this can be caused by a corrupt file, which would also explain everything. Does anyone know what file I should look for?

8.) I have an old backup of the complete file system (circa 2009). Would it make sense to dump everything on the nuvi and replace with this backup? Any hints or things to look out for?

9.) Since I can access the file system, I can also download tracks, etc. with MapSource. The last day I used the GPS successfully was July 1, when it worked perfectly for a 300 mile trip. There were no tracks after June 30, which is weird.

10. Since there are no tracks, this also explains why the Secure Location does not unlock it.

11.) Garmin support is of no help except they want $150 to "fix."

Thanks for any suggestions for how to recover the gps!

Open the case. unplug battery, let capacitor discharge (hours, days, weeks?) or force the capacitor to discharge, plug it back in and the locking problem should be clear.

Thanks, but this is an 855 so opening the case isn't necessary to remove the battery. The battery has been disconnected for a week as an experiment. The problem appears to be in the non-volatile memory.

It seem that you might not have a choice but to send it in to Garmin and pay the 150 or buy a new gps.

It sounds to me like you have a hardware issue. It could be a bad touch screen, and the 855 is probably not worth the cost of repair. I wouldn't pay Garmin $150 to repair/replace an 855 unless you need to protect an investment in a lifetime map update. Even then it is questionable as you can easily buy a refurb 855 for $99 or less.

UPDATE:

I was able to get the Garmin working again after not being able to even enter my PIN earlier. It was a pretty long process but it's working great now. The issue was software all along. I suspect it was a corrupt file, although I have no idea which file was causing the problem.

Care to share with us how you succeeded in doing this