Hello,I am Pete, and I'll be happy to assist with your question today.
The PIN is a security and anti-theft feature.
If you have forgotten the pin, you will need to drive to the security location you programmed when you first setup the device.
Driving to the security location will unlock the GPS in the event that you do not remember your PIN.
If that does not work, you will need to send the GPS to Garmin to be reset.