What if you are 120 days late and you pay the balance owed can they still repo your car?

If by "pay the balance owed" you mean "pay off the debt completely" then no, they cannot.

If you just mean "make up all the missed payments," it's murkier. You should contact the finance company immediately, because generally they don't really want the car, they want the money, and if they think they can get it without taking the car, they'll jump at the chance since it's a lot less hassle than going through the whole reposession process.