Abstract: An emissions validation system is comprised of a plurality of sensors (42), (36), (26) and (34) for monitoring the various emissions and diagnostic aspects of a vehicle (10). An emissions validation system (18) is operable upon refuelling through a refuelling line (20) to interface through an interface (14) to a CPU (28). The CPU (28) retrieves the stored dam and transfers it through the interface (14), through an electrical line (22) to a main CPU (26) in the emissions validation system (18). The main CPU (26) then evaluates this dam, in addition to monitoring the amount of fuel that is placed back into the vehicle's tank (32). This allows a complete record of the vehicles history to be maintained.