What Chicago's Emissions Test Requires
Chicago requires an emissions test every two years for most vehicles, and the test checks whether your car's exhaust meets state pollution limits. The test itself takes about 10 minutes and costs between $15 and $30, depending on which testing station you visit. You'll drive onto a dynamometer — a machine that measures what comes out of your tailpipe while your engine runs at different speeds — and a technician records the results.
The test covers three main pollutants: nitrogen oxides, particulate matter, and hydrocarbons. Your vehicle passes if all three fall below Illinois limits. If you fail, you have 30 days to fix the problem and retest at no additional charge at the same station. The retest is free even if you go to a different station, as long as you bring your failed test receipt.
Diesel vehicles, motorcycles, and vehicles registered outside Illinois are exempt. Vehicles newer than the current model year are also exempt for their first four years. If your vehicle is 25 years old or older, you may be exempt depending on when it was registered — check with your testing station to confirm.
Key Takeaways
- Chicago emissions tests cost $15 to $30 and take about 10 minutes at any state-certified testing station.
- Your vehicle must pass every two years, and you can find your test due date on your registration renewal notice.
- If you fail, you have 30 days to repair your vehicle and retest for free at any certified station.
- Diesel vehicles, motorcycles, and vehicles 25 years or older may be exempt, but you should confirm with your testing station.
- You cannot register or renew your vehicle without a passing test result on file with the Illinois Secretary of State.
Where to Get Tested in Chicago
The Illinois Secretary of State maintains a list of certified testing stations throughout Chicago and Cook County. You can search by ZIP code on their website to find stations near you. Most are independent repair shops, gas stations, or dedicated emissions testing centers. Call ahead to confirm hours and whether they accept walk-ins or require appointments — many stations book up during peak times, especially near the end of the month.
Testing stations are required to display their certification and pricing clearly. If a station quotes you more than $30 or refuses to show you their certificate, that is a sign to find another location. Some stations offer discounts if you test multiple vehicles or if you bring your own vehicle rather than having it towed.
What Happens If You Fail the Test
A failed test means your vehicle's emissions exceed Illinois limits in at least one category. The testing station will give you a printed report showing which pollutants failed and by how much. Common reasons for failure include a faulty oxygen sensor, a loose gas cap, a clogged air filter, or problems with the catalytic converter.
You have 30 days from the test date to fix the problem and retest. During those 30 days, you can still drive your vehicle legally — the test failure does not suspend your registration. However, you cannot renew your registration without a passing test result. If your 30 days expire without a retest, you will need to pay for a new initial test and start the 30-day window over.
Take your failed test report to a repair shop and ask them to diagnose the issue. Many shops can identify the problem quickly by reading your vehicle's onboard diagnostic codes. If repairs are expensive, get a second opinion before committing. Once repairs are complete, return to any certified testing station with your failed test receipt to retest for free.
How to Prepare Your Vehicle for Testing
Before you go to a testing station, make sure your vehicle has been driven for at least 20 minutes so the engine reaches normal operating temperature. A cold engine can produce higher emissions readings and cause a false failure. Also check that your gas cap is tight — a loose cap triggers the check engine light and can cause a failure even if your emissions are otherwise fine.
If your check engine light is on, have the codes read before testing. Some diagnostic codes will cause an automatic failure regardless of your actual emissions. You do not need a full tune-up before testing, but if your vehicle is overdue for an oil change or air filter replacement, those are inexpensive fixes that sometimes improve emissions results.
Bring your vehicle registration or proof of ownership to the testing station. You will also need to provide your vehicle identification number (VIN), which is on your registration and on the dashboard at the base of the windshield on the driver's side.
Renewing Your Registration After Passing
Once you have a passing test result, the testing station submits it electronically to the Illinois Secretary of State. You do not need to do anything — the result appears in their system automatically within one business day. When you renew your vehicle registration online, by mail, or in person at a Secretary of State office, the system checks for a valid passing test and will not let you complete the renewal without one.
If you renew your registration before getting tested, your renewal will be rejected. You can still renew after you test — just complete the renewal process again once your passing result is in the system. There is no penalty for the delay as long as you test before your current registration expires.
Your registration renewal notice will show your test due date. In Chicago, most vehicles are due every two years from the month they were last tested. If you are unsure whether you need to test, call the Illinois Secretary of State's emissions hotline or check your registration documents.
What to Do If You Cannot Find a Testing Station
If you live in an area where testing stations are far away or have long wait times, you can request a waiver from the Illinois Secretary of State. A waiver postpones your test requirement for up to one year, but you must request it before your current test expires. Waivers are not automatic — you need to show that no certified station is within a reasonable distance of your home or workplace.
Contact the Illinois Secretary of State's emissions program directly to request a waiver. Have your vehicle registration and VIN ready. They will ask for your ZIP code and may ask you to document which stations you contacted and why they were not accessible. Waivers are uncommon but available for genuine hardship situations.
Frequently Asked Questions
Can I test my vehicle before my due date?
Yes. Testing early does not hurt, and your new test date will be two years from whenever you test. If you are close to your due date and worried about scheduling, testing a few weeks early is a reasonable option. The testing station will not charge extra for an early test.
What if I move out of Chicago but still own a vehicle registered here?
You must still pass an Illinois emissions test to renew your registration, even if you now live in another state. However, if you change your vehicle's registration to your new state, you are no longer subject to Illinois testing. Contact the Illinois Secretary of State to understand how your move affects your registration status.
Do hybrid or electric vehicles need emissions testing?
Hybrid vehicles do need testing because they have a gas engine. Electric vehicles with no gas engine are exempt. If you own a plug-in hybrid that can run on gas, you will need to test it.
What if the testing station says my vehicle cannot be tested?
Some vehicles have mechanical problems that prevent testing — for example, if the engine will not start or the transmission is stuck in park. The station will give you a written explanation. You will need to repair the vehicle first, then return to test. This is different from a failed test and does not start your 30-day repair window.
Can I test my vehicle in a different county and still renew my Chicago registration?
Yes. As long as the testing station is certified by the Illinois Secretary of State, the result is valid for registration renewal anywhere in Illinois. You do not have to test in Cook County or Chicago specifically.