Yesterday, I took my Honda Accord in for servicing at a local repair shop. A few hours later, the owner of the shop called me to tell me that my car was ready to go, with a new battery.
When I started my car, I noticed that the car's dashboard touch screen was asking for a PIN since the power had been removed. I found a piece of paper, in my glove compartment, with a four digit PIN that I tried a few times until I was locked out of the system.
I took the car to a local Honda dealer where a customer service rep explained the differences between a radio unlock PIN and a navigation PIN. Basically, the radio PIN is entered using the knob that tunes in radio stations and the navigation PIN is entered through the dashboard touch screen.
Since I had locked myself out of the navigation PIN, I had to disconnect the battery for about ten minutes and then try again. An audio technician, who had done work on my navigation system, sent me the serial number for my unit. Then, using my VIN and serial number, I was able to retrieve my four digit PIN to enable the navigation system.
The key lesson I learned was, obviously, to keep my PINs and serial numbers handy. If Honda didn't have them on record, I'm not sure what I would have done.