Can a co signer take the car and refuse to give it back enen though a payment plan has been made with the creditors?

IF BOTH OF YOUR NAMES ARE ON THE LOAN AND ON THE REGISTRATION THEN YES THAT PERSON CAN TAKE THE CAR AND NOT GIVE IT BACK. BUT IF IT IS REGISTER WITH THE STATE ONLY IN YOUR NAME THEN NO. AND IT BECOMES A STOLEN VEHICLE. BUT IF THE VEHICHLE AND THE REGISTRATION ARE BOTH IN YOUR NAMES AND THAT PERSON DOES NOT WANT TO GIVE IT BACK THEN YOU NEED TO GO TO THE LENDER AND TELL THEM WHAT IS GOING ON.