Article in English: Many states require periodic emissions tests to be performed to ensure that your car is running as clean as possible and not contributing to excessive air pollution. There are a lot of complicated numbers associated with the process that are probably not of interest to the average driver and vehicle owner, but you can research the Environmental Protection Agency standards for all vehicles here.  You don't need to know the standards to have your vehicle tested. All you need to do is find a testing location in your area and schedule an appointment. They'll tell you if your vehicle is up to the standards, and help you get it to code if it isn't. You can help avoid problems by keeping up on the maintenance of your engine fluids and filters. You should have your exhaust system checked periodically for any issues that may cause a future failure. If your check engine light comes on, have it serviced quickly to prevent further problems. Emissions testing is different for different types of vehicles,  and is required for a vehicle to be street-legal in some states, while in others there's no requirement at all. Motorcycles are required to be tested in some areas, but not in others. Check with your local bureau of motor vehicles to make sure your vehicle needs to be tested. The most common exclusions are:  Vehicles manufactured pre-1975 Diesel vehicles manufactured pre-1997 Electric vehicles and hybrids Trailers Failing the emission test is likely the result of some common performance issues in your vehicle. Learning to anticipate and correct these issues can help you pass the emissions test, once you've got it scheduled. The most common system failures are:   Out-of-spec fuel metering: This could be the result of the CPU, if your vehicle has one, or the fuel injection and carburetor unit.  Worn-out spark plugs: These can cause hydrocarbons to spike during the examination. Just basic maintenance on the engine can sometimes cause emissions to spike.  Vacuum leaks: These can occur because the MAP sensor is dysfunctional,...

Summary in Vietnamese:
Kiểm tra tiêu chuẩn phát thải và quy trình tại nơi bạn sinh sống. Tìm nhóm xe cụ thể của mình. ’’’Phun khí và EVAP trục trặc’’’: