Gap Insurance - does it make up the gap to the whole amount payable on the car?

yes it does cover the difference between what you owe and the actual value of the car. but if the car dealership is trying to sell it to you for what i am going to guess from my experience in auto sales and finance is about $499.00 . don't pay it contact your insurance company they will sell you gap for less than half of that, if you need it at all .go to kbb.com and and it will give you the actual value of the vehicle if what you are financing is less than that number and you plan on taking care of the car and stay under 14000-17000 miles a year you may not need it at all