Considering motor vehicles are considered a major source of air pollution, learning how to pass an emissions test is not only crucial when it comes to getting your tags every yet, but if you fail to do so, then your vehicle is negatively impacting the environment and air quality in general. Due to the level of pollutants that cars contribute each year, the EPA, also known as the Environmental Protection Agency, prescribes strict emissions standards, which is why every state conducts esmissions tests, in order to ensure a vehicle will meet those standards. If you’re not sure how to pass an emissions test, or whether or not your vehicle even can, I’ll go over some helpful tips that will make your vehicle test-ready so you can be sure your vehicle will pass the first time around.
How to pass emission test:
- Buy an OBD2 scanner and run diagnostics to determine if there are any underlying issues and what repairs you can make to ensure your vehicle is emissions testing ready.
- Routine maintenance is essential. Replace spark plugs as needed, routine oil changes, and other routine maintenance tasks
- Have a pro inspect your vehicle prior to the big day
- Ensure your tires are aired up at the correct pressure and that all tires are balanced
As you can see, keeping up on your vehicle’s routine maintenance needs is often the key to ensuring you pass your emissions test with flying colors. Read on to learn what you can do to pass, what repairs you can try, and how you can clear that dreaded check engine light.
What Are Emissions Tests?
An emissions test is designed to ensure that the level of toxic gasses produced by a vehicle doesn’t exceed a certain limit. These tests will measure the level of tailpipe emissions produced by a vehicle’s engine to determine whether or not a vehicle meets the strict regulations regarding specific pollutants. These tests will measure levels of:
- Non-methane organic gases
- Particulate matter
- Carbon monoxide
- Nitrogen oxide
Should your vehicle fail to pass this test then you will not be able to drive it legally or register it.
If you’re not sure whether or not your vehicle can pass, learning about the common causes for a failed test can help you determine whether your vehicle needs to be taken in for a tune-up and repairs prior to taking the test.
Depending on the state you reside in, there are a few types of tests that a vehicle will go through. As an example, in some states, vehicles manufactured in 1996 and newer will need to undergo an onboard diagnostics system check. A vehicle that was manufactured between 1981 and 1995 will need to go through a maintenance and inspection test. If you’re not certain which tests will be conducted, check out your state’s emission testing regulations for your vehicle.
What is an OBD Test?
The OBD test will involve checking the car, SUV, or truck’s OBD system for any possible emissions-related issues. This test will determine if the equipment designed to control emissions is in working order. One way you can check this on your own is to use the best OBD2 scanner. You can purchase one and run a variety of diagnostics tests on your vehicle. One of these devices will pull up any problem codes from your vehicle’s computer and tell you exactly what’s going on with your vehicle. If you’re looking for an affordable, beginner-friendly model that’s also highly accurate, I recommend the MAOZUA Latest V7.7 Creator C310+ OBD2 Scanner.
Inspection and Maintenance Test
For this test, the vehicle is operated on a dynamometer, which is designed to simulate driving. During this test the vehicle’s exhaust emissions will be captured, then analyzed. A gas cap test is also part of a standard inspection and maintenance test and it’s simply a matter of determining whether or not the gas cap is leaking.
What Can Cause a Failed Test?
For the most part, you can easily resolve any issues that can lead to a failed test. Some of the most common reasons behind a fail include the following issues:
- Rich Air-fuel: This issue can be caused by an injector that’s malfunctioning. It can also be caused by an oxygen sensor that’s faulty. In some cases, too much raw fuel can be dumped through the system, causing it to burn out the vehicle’s catalytic converter.
- Spark plugs: Worn out spark plugs can cause an increase in emissions gases, which is why you should have a tune-up prior to an inspection.
- Defective EVAP system: Defects in the EVAP system can cause vapors from the gas tank to pollute the air. Leaking vents and hoses are often to blame for a defective system.
- Gas cap leak: This issue is a simple fix. Many vehicle owners don’t usually worry about a leaky gas cap, however, it can easily cause you to fail an emissions test. If you’re dealing with this issue, make sure you replace the cap with one that properly seals the tank.
- Faulty check engine light: Even if all of the systems in your car are in proper working order, you can still fail the test if you have a faulty check engine light.
- Air filter: A dirty air filter can cause high levels of hydrocarbons, which is just another reason you should check and replace your vehicle’s air filter often.
- Catalytic converter: Make sure you inspect your vehicle’s catalytic converter carefully, before an emissions test. If the catalytic converter is damaged then it will not be able to convert the toxic gases into gases that are not harmful.
Get an Inspection
If you want to keep your vehicle street legal, then you need to make every effort to prepare it for the upcoming test. Since most of the issues are caused by failing to maintain your vehicle, properly taking care of it and performing routine maintenance such as replacing the air filter and changing the oil can easily prevent your vehicle from failing. Before you take your vehicle in for an emissions test, I recommend having a pro inspect it to determine if any parts or components need to be replaced or repaired.
What Else You Can Do to Ensure You Pass
- Avoid taking the test if your vehicle doesn’t seem to be running right. This will only result in money wasted. Take your vehicle to a pro and have it inspected instead.
- Air up your tires. If your vehicle is older than 1999 then it will be driven on a dynamometer as a sample of its exhaust is obtained by a machine. Make sure your vehicle’s tire pressure is correct and even, which can help you pass. With the right pressure, the vehicle will be driven with a higher level of stability and more control, which will significantly improve your chances of passing.
- Make sure you take your vehicle in for a tune-up often. If you don’t have the cash, you can learn how to change brake rotors, sparkplugs, and the oil on your own by asking a friend with experience or searching online for tutorials.
Should I Change the Oil Prior to a Smog Check?
The oil hasn’t been changed within the last five thousand miles, I recommend having it changed. This can help you pass the test because the vehicle’s PVC system is designed to allow the engine to breathe the fumes from the oil compartments. These fumes will then be burned via the combustion process. If a vehicle’s oil is contaminated because you’ve failed to stay on top of oil changes, then it can easily prevent you from passing.
Will Going for a Long Drive Prior to a Test Help Me Pass?
Yes. Take a twenty-minute drive before the test to ensure that oil, coolant, and catalytic converter maintain and reach an optimum operating temperature. To achieve adequate combustion and pass a smog check the engine needs time to warm up. Driving approximately fifteen miles can easily achieve this.
Can the Weather Impact My Smog Results?
Yes. Try to take the test on a nice day. Always avoid rainy weather. A vehicle must be driven on a dynamometer during the test. When a vehicle’s tires are wet they will lose traction as the smog tech attempts to maintain the correct speed. Unstable drivetrain and engine torque is not going to leave your vehicle in the best running condition and can place undue stress on the engine, despite the fact that some of these machines do have a dry tires mode.
How to pass emission test can be as simple as staying on top of your vehicle’s routine maintenance, which includes changing the oil and spark plugs as needed. If you’re currently dealing with a check engine light, make sure you purchase an OBD2 scanner and run diagnostics on your vehicle so you can make the necessary repairs before taking the test.