Back to all

Passing the Test (How to Prevent Emissions Test Failure)

July 21, 2024

Vehicle emission testing has become ubiquitous in North America and for a good reason.  Clean air quality is important for the environment and all of us.  Since vehicle emissions are among the main causes of air pollution, emission testing can alert you to problems in your vehicle than can be fixed so it won't needlessly pollute.

Emissions tests are looking for certain toxic gases internal combustion engines produce, such as nitrogen oxide, particulate matter, non-methane organic gases and formaldehyde.  Emissions control systems reduce these gases if they are working properly. 

The best way to minimize pollution is to keep those vehicle systems working properly, and periodic inspection and maintenance is the key.  So if you want to make sure your vehicle will pass an emissions test, it helps to know what might go wrong.

Let's start on the easy one.  Your gas cap could be loose, allowing vapors to escape into the atmosphere.  The most common solution is to replace it.  Or your air filter may be dirty.  A dirty air filter may push your hydrocarbons pass the acceptable level.

Now to the more complicated things.  The mixture of fuel and air in your engine may be tilted toward the "too much fuel" side.  That could cause problems for your vehicle's catalytic converter, a device that converts toxic gases from your exhaust into less toxic pollutants.

Your vehicle has a closed system that prevents fuel tank vapors from escaping into the air; it's called the EVAP system.  A technician can track down problems.

Vehicle engineers have gone to great lengths to minimize the amount of pollution your vehicle produces.  Your vehicle's manufacturer recommends how frequently those systems need servicing.  Keep those systems in good shape and you're likely to pass emissions tests with flying colors.  Neglect them and you might find your vehicle failing an emissions test.  When that happens, you'll have to get the problems repaired before you can get back on the road.

Tuffy Auto Service Center Elgin
395 S. Randall Rd
Elgin, Illinois 60123
847-717-4682

Need Service?

Request a Quote

More articles from Tuffy Elgin

Go with the Flow (MAF Sensor Replacement)

February 1, 2026

If your vehicle has an internal combustion engine, it depends on two things to make propulsion power for you to be able to motor on down the road: fuel and air. The engine mixes the two in just the right proportion so that they can be ignited, creating a series of tiny explosions that are coordi... More

See the Light (Bulb Replacement)

January 25, 2026

When you notice one of your headlights has gone out, its important for the safe operation of your vehicle to get it changed and working again. Not only is replacing a headlight important for your ability to see in the dark, but its also vital that it be lighting your way and aimed correctly so o... More

Stop! And See Us (Brake Pad Replacement)

January 18, 2026

If youve ever driven a bicycle with hand brakes, youll probably understand how the brake pads on your vehicle work. Bicycle brakes use a system that squeezes the bike wheels rim with a pair of cushioned pads activated by your hand squeezing the hand brakes on your handlebars. The friction of tho... More