Emission System

How To Pass Emissions Test? (3 Useful Tips For You)

Mike Cross
Updated Jul 31, 2021
how to pass emissions test

The dreaded emissions test is coming eh? That means it’s time to get your car in tip-top shape and make sure there won’t be any embarrassing surprises when you get to the testing center.

We’ve all been through this, especially those of us that live in major metropolitan areas. Let’s take a look at what to do and how to pass an emissions test.

3 useful tips to Pass Emissions Test

Find any quick fixes

This is one of the places where so many people go wrong. Even those who aren’t mechanically inclined can make quick adjustments under the hood to get everything in proper order.

Check the timing belt, for instance. If it is a word, shattering, or appears to be in disrepair, the car will likely fail the test (not to mention need major work done if it breaks.) Have a mechanic look at this.

Look at the spark plugs and check to make sure you have enough oil. Another super simple hint is to gas up before you get the emissions test, as the engine will function at a more optimal level if the gas is filled and there is no chance it is running on fumes or burning inefficiently.

We always recommend running a quick scan tool to see if anything comes up, even if the check engine light is not on. If you don’t have one, just head up the street to the nearest parts store or buy it online. They will have one and will likely check your engine for free. They can also advise on any parts that need to be purchased or maintenance that needs done before heading to the emissions test. When thinking about how to pass an emissions test, running an OBD scanner is a great option.

Complete your check under the hood

How has the car been burning gas lately? If you suspect you aren’t getting optimal gas mileage, that is a good sign that you won’t pass the emissions test. A lot of new vehicles have two fuel control modes, designed to run in different situations and produce different results. Varying levels of gas will be burned in these situations, so make sure you know which one you are on and keep the car in the lesser of the two. A quick search on the internet can show you how to do this with detailed instructions and professional pointers.

Another thing to note is the oxygen sensor. If you question the car’s emissions, you’ll want to have a good understanding of how the reading is laid out. Note if there is quick switching between high and low values – this signifies changing fuel loads affecting the oxygen.

Make sure your MAF (mass flow sensor) is neat and in good working order, if you have one. If it reads well, the vehicle is in good shape for passing the emissions test. After all, isn’t the test about the flow of emissions?

Have a mechanically inclined friend do a test drive

Test the cat, look at the exhaust pipe while the car is running, and get a general feel for how it feels when driving, when revving, and when accelerating a rapid pace. All of these are factors in the emissions test.

If you don’t feel comfortable analyzing this, ask a friend who knows about care. We all have that one guy who just knows everything and is always looking to test drive a vehicle. This is time to take advantage of those offers!

We noted above the importance of checking the exhaust. Initially, look in the rear-view mirror while driving down the road and see if you notice more fumes than normal. This is indicator number one.

Next, put the car in neutral and have either yourself or the mechanically inclined friend stand behind the car. Rev the engine and observe the fumes that come out of the tail pipe.

The exhaust is one of the biggest factors they will measure during the test. The tester will rev the engine in a hardcore manner, testing out how well the car handles pressure. If it isn’t keeping the emissions under whatever the required limit is in your area, than you are automatically going to fail the test.

Most newer vehicles are able to handle the test without much problem, as long as you keep up on maintenance. If something seems out of place, get it looked at. If the check engine light is on, the car will fail automatically.

Car repair shops will often fix a problem for free if they fail to fix it properly the first time. If you fail the test after having them look at a specific problem that the emissions tester addressed, the fix should be complimentary. Keep this in mind and don’t be afraid to press for answers.


Emissions tests are a royal pain, but ultimately they help to keep the air cleaner in highly congested cities. No one wants to be driving around in smog, and that’s what would happen if there were no requirements for emissions. Try to view the test, and how to pass an emissions test, as a duty to society, like jury duty. Everyone must do their part!

If you have enjoyed this article, please share on social media so that others learn how to pass an emissions test. Got a tip? Leave it in the comments below!

Mike Cross
Life is too short to drive with stock audio

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2 comments on “How To Pass Emissions Test? (3 Useful Tips For You)”

  1. My friend wants his car to get an emission test. I like how you mention before doing the emission test you should run a quick scan on your vehicle to see if anything comes up. Thank you for the advice. I'll recommend this to my friend before he takes his car to an auto service.

  2. I like how you mentioned that even though you aren't mechanically inclined you can still check quick fixes like the timing belt. My sister is thinking about taking her car into a star certified smog station because her vehicle is due for an emission test and she wants to make sure her automobile passes. It seems like a good investment for her to hire a reputable professional that can make sure her car is following all the state regulations for safety requirements.

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