It is not easy. As you have said, the radio is 'married' to the car by the NATS system.
If the radio is installed into another car, the "SECURE" error message will appear. The radio will not operate.
You have two options to replace the radio.
A) Have this work done by a NISSAN dealer. They should have a special diagnostic device that can 're-marry' the radio to your car.
B) Bring the 'new' radio to a decoding professional who may be able to modify the firmware so the radio no longer does the NATS check. The special EEPROM programmer and soldering skills are required to do so. There is no procedure (like button-sequence) to reset the radio.
Some people state that their radios have switched to the "CODE" message after 1-2 hours of being turned on. But I do not think that you should hope on it. Most likely, it will be stuck on the "SECURE" message. Anyway, if you see the "CODE" message, you will need the correct code for your radio.
Important Note: If you're happy to see the "CODE" message, do not try to guess the code. If you enter approx. 17-20 invalid codes, the radio unit will be rendered inoperable. ONLY a decoding professional can revive the radio when it says "LOCKED".
1, October 2012
