How the GM money-back guarantee program works

Here are details of General Motors' new money-back guarantee program, which starts Monday.

* Cars must be a new 2009 or 2010 Chevrolet, Buick, Cadillac or GMC purchased between Sept. 14 and Nov. 30.

* Vehicles can be returned between 31 and 60 days after purchase, and cannot have been driven more than 4,000 miles.

* To qualify, owners must be current on financing payments.

* Buyers who return cars will be repaid the purchase price, excluding dealer-installed accessories such as undercoating.

* If a buyer trades in a car worth less than the amount owed on it, that difference -- which dealers often cover -- will be deducted from the refund. This occurs, for example, when a buyer trades in a car worth $5,000, yet owes $7,000 on its loan.