Did your vehicle fail the Illinois emissions test, AKA smog test? Don’t feel bad, it happens to the best of us.
Sometimes our cars develop problems that we are too busy to notice. Or, they inconveniently begin having problems the day you plan on driving to get the test done.
Emissions Testing Basics
Illinois law says that you must test your vehicles every two years, starting 4 years from the day of sale. There are a few exceptions for those living in certain zip codes. You can find that information here.
Nearly all emissions testing is due just before or on the date of your registration renewal. If your car doesn’t pass the test, you can’t get the current year registration.
Hopefully, you don’t wait till the last minute. By having done the test a few weeks beforehand, you will still have some time to repair your vehicle if it doesn’t pass the emissions test.
A Few Tips about This Process
If your vehicle fails the emissions test, but you can’t afford the repairs, Illinois has a Hardship Waiver. There are certain requirements that you must meet. You can find those details here.
Many auto parts or mechanic shops will check your vehicle for codes to let you know if something is wrong for a minimal charge. This way, you can make repairs before you have the emissions test performed.
Common Reasons for Failing the Emissions Test
Failing an emissions test could be due to any number of problems. However, there are a few codes that seem to crop up more often than others, including:
- Faulty Evaporative Emissions Control System – Don’t let the big-name fool you. This simply refers to the gas vapors in the fuel tank and fuel system. These are trapped and partially reused so the vapors don’t get released into the air. A gas cap that no longer fits tightly, vacuum hoses and vents are often the most common issues.
- Fuel Metering – This stems from any number of problems, such as an ECU that isn’t metering out the fuel properly, to a bad fuel injector.
- Failed Air Injection System – Fresh air from the outside is forced into the exhaust to help dilute the exhaust gases. If the air injection system fails, the exhaust gas levels of carbon monoxide and hydrocarbons are too high.
- Failing Oxygen Sensor(s) – This sensor monitors the amount of oxygen in the exhaust gas of your vehicle. Over time, this sensor becomes clogged or it stops working. So, it is best to get the O2 sensors replaced. Your vehicle might have more than one.
- Rich Fuel Mixture – Your car must have just the right mixture of both air and gas to run properly and prevent it from allowing too much-unburned gas to pass to the atmosphere. When this occurs, the problem is referred to as a “rich” mixture. There are multiple causes for this; everything from leaking fuel injectors to excessive fuel pressure.
- Problems in the Ignition System – When a vehicle has very high levels of hydrocarbons, it often stems from a car that has not been well maintained. Ignition system issues can mean the spark plugs are very worn, the distributor cap is worn out or cracked, or the spark plug wires are crumbled. Regular tune-ups will help prevent this from occurring.
Lessons Learned
While we can’t avoid every ugly thing life may throw at us, you can prevent your vehicle from failing a smog test again by following these three rules
- Perform scheduled maintenance as noted in your owner’s or service manual.
- Have the car repaired if the Check Engine light comes on. Ignoring it will only cause you more problems later. Worse still, if the tester sees that the light is on, it’s an instant fail.
- Don’t believe that removing the battery cable for a few minutes will “reset” that Check Engine light and your car will pass. If you own a 1996 vehicle or later, the Check Engine light will go out but the codes are still in the computer. These codes can cause rejections. Your vehicle will be rejected because of those codes.
Pro Tips
Mechanics say that doing the following before the test will help increase the chances that your vehicle will pass:
- Change the air filter.
- Change the oil if it is dirty.
- Put premium gas in the car (yes, it’s expensive but cheaper than failing the test).
- Properly inflate the tires.
- Be sure to drive the car for at least 15-20 minutes before the test and remove any unnecessary junk in the trunk or rear hatch. If you can get on the freeway and drive at 55mph for 10 or 15 minutes, it’s all the better.
What to Do if Your Car Failed the Emissions Test
Don’t panic and start thinking about how you will manage to get by without a car. You can often ask for an extension if time is running out.
The one thing you should do is to take your car to a qualified, state-certified repair location as soon as possible.
Don’t drive yourself insane with anxiety imagining that the repair costs are going to clean out your bank account. The average repair across the US is $357. This isn’t an insurmountable amount of cash for most people. Keep in mind, your repair might be far less.
You will feel a huge amount of relief when you’ve repaired your car, received your renewed registration, and get your family back on the road again.
Don’t waste time testing your vehicle if the Check Engine light is on or if it isn’t running its best. Call or come over to My Mechanic for a complete inspection before you hit the emissions testing site. You will be pleasantly surprised at how easy it can be to pass that emissions inspection after allowing your car to spend a little time with the professionals from My Mechanic.
