California DMV: Can't Renew Registration Online

Yup, I agree with Alan. Any documents you have that help to show that the car changed hands and left the state will benefit you. The more the better, even if they aren’t hard evidence by themselves. Coupled with a statement of facts you might have enough to get any back fees they want to charge you waived.

I’ve been able to get back fees waived like that in the past. When I bought my EL5 GT it was supposed to be “out of the system”. It turned out it was not, and several years of back fees were due (in addition to a couple other headaches). Part of the statement of facts I filed was that the car wasn’t currently operable and hadn’t been used on California roads in the time the back fees would have been due. The fees were waived. Part of that was the fact that I was unaware of all of that when I purchased the car. It definitely depends on the situation and what kind of mood the clerk and supervisor are in that day. But it’s worth a shot.
I canceled the "Vanity" plates when I sold. it. I told DMV it was sold out of state, might help..