CO2 emissions refer to the release of Carbon Dioxide in the exhaust gases of a car, and are a good measure of the amount of fuel a car is burning. The g/km is a measure that quantifies the weight of Carbon Dioxide released for every Km that the car is driven and so makes it a good measure of the Fuel Economy of the car.
Different information in a vehicle's history can indicate an accident or damage, such as: salvage auction, fire damage, police-reported accident, crash test vehicle, damage disclosure, collision repair facility and automotive recycler records. Not every accident or damage event is reported and not all reported are provided to CARFAX. Details about the accident or damage event when reported to CARFAX (e.g. severity, impact location, airbag deployment) are included on the Vehicle History Report. CARFAX recommends you obtain a vehicle inspection from your dealer or an independent mechanic.