How to Pass the Emissions Test

Emissions tests are typically conducted in certain regions to help reduce the carbon footprint from vehicles. These mandatory tests can be daunting for those who drive regularly. However, understanding the emission standards in your area, how to prepare for the test, and equipping yourself with the best chance of success can require significant effort. If you own a vehicle, see Step 1 for more details on how to pass the emissions test.

Check emission standards and testing procedures in your area. Many places require periodic emissions tests to ensure your vehicle is running as cleanly as possible and not contributing excessively to air pollution. There are many complex figures associated with this process, which many regular drivers and vehicle owners may not be fond of, but you can find out about the standards from the Environmental Protection Agency for all vehicles here.

• You don’t need to know all the standards for your vehicle’s test. All you need to do is find a testing location in your area and schedule an appointment. They will let you know whether your vehicle meets the standards and help you get it up to code if it doesn’t.

Identify your specific vehicle group. Emissions tests vary by vehicle type and are required for road use in some areas, while others do not mandate them. Motorcycles may also be required to undergo testing in some places but not others. Check with your local inspection authority to ensure your vehicle needs to be tested. Common exceptions include:

• Vehicles manufactured before 1975
• Diesel-powered vehicles manufactured before 1997
• Electric and hybrid vehicles
• Trailers

Understand the underlying causes of emission issues. Failing the emissions test often results from several fundamental operational issues. Learning to anticipate and address these problems can help you pass the test since you will have a plan in place. Some of the most common system faults are:

• Out-of-spec fuel measurement: This could be caused by the CPU (if your vehicle has one), the fuel injectors, or the carburetor.
• Worn spark plugs: This can lead to an increase in hydrocarbon compounds during the test.
• ’’’Vacuum leaks’’’: This may occur if the MAP sensor isn’t functioning properly or if there’s an issue with the vacuum hoses.
• ’’’Malfunctioning air injection and EVAP systems’’’: If the air injection system in the engine fails, it won’t properly control hydrocarbon and carbon monoxide emissions.

Plan your vehicle test. Take your vehicle to a local emissions technician to check if there are any overlooked issues before your test. Typically, emissions testing is available at oil change stations and shops like Jiffy-Lube. Find one in your area and schedule your test.

• If your vehicle is running well with no apparent “issues,” it doesn’t necessarily mean it will pass the emissions test. Many vehicles may continue running smoothly even though they fall short of local government standards.

Ensure the check engine light is off before your appointment. If your vehicle’s check engine light is on during the test, you will automatically fail the emissions test. If you're unsure of the issue, an emissions repair shop will perform diagnostic tests to resolve it.

• Your vehicle must be up to date for testing, meaning even if the technician identifies an obvious problem that would lead to a failure, the vehicle will certainly fail. For example, if you know your vacuum hose is leaking or if the check engine light is on, you need to fix these issues before going for the test.

Start your vehicle before taking the test. Drive for at least 20 minutes before heading to your emissions testing location. This will give your vehicle enough time to reach the ideal temperature for the coolant, oil, and proper pressure for the catalytic converter, ensuring you get accurate results.

Maintain proper tire pressure. Proper tire pressure reduces strain on your engine, improving your chances of passing the emissions test. Balancing the vehicle’s weight distribution as the technician drives it helps increase the likelihood of a successful test. It’s best to inflate your tires to the correct pressure before taking your vehicle for the test.

Choose a dry day for the test. Since the dynamometer will be used during the test, driving on an incline could affect the vehicle’s traction, which can influence engine performance and potentially cause a test failure. Maximize your chances of passing by scheduling the test on a sunny day with good weather conditions and clear driving conditions.

Change your engine oil regularly. If you haven’t changed your oil in over 8000 km, it’s time to do so. If you’ve changed the oil within the last 8000 km, it’s still a good idea to replace it again before taking the car for testing. Plan to get an oil change or do it yourself before the test.

Change your oil regularly. The air and oil filters need to be replaced periodically to keep the engine running efficiently and to minimize harmful emissions. Refer to the user manual for specific details regarding the mileage intervals, and plan for timely replacements.

Use fuel additives if suitable for your vehicle. Check the user manual to determine whether using Premium oil is appropriate for your vehicle model. Other additives, like Clean Sky Clean Air, can be added during refueling to help clean carbon deposits from the engine during regular operation.

Adjust the carburetor for the right fuel and air mixture. Running an overly rich fuel mixture can have long-term effects on the engine's ability to manage hydrocarbon and CO emissions. It’s best to periodically check whether your engine is running too rich or lean to ensure it stays within the optimal parameters, keeping your engine in good working condition.

• Avoid wet weather on the day of your test. Humidity and rain can affect your vehicle’s temperature, causing it to run below optimal conditions. While it is still possible to pass the test on a rainy day, it will be more challenging.
• Don’t schedule your emissions test if your vehicle is not running well. Even if your vehicle shows no obvious external issues, it can still fail the emissions test. If your vehicle is experiencing problems, you are unlikely to pass the test.
• Fuel additives can help reduce emissions. These additives are typically added during refueling at gas stations. They help clean the vehicle’s internal system, allowing for better fuel efficiency and improved overall engine performance.