Hello. I bought an used car and the battery run down and after restarting the Pioneer Avic-F980 DAB requires the password which is not available. Also showing some hints.. Any advice on how to solve it will be appreciated 

This method works on AVIC F980 DAB and many newer models:

https://avic411.com/uploads/monthly_2019_01/password.jpg.e1023850ae2219e91faa9c330350bc45.jpg