Does My Car Need an Emissions Test in Illinois?

If you live in the Chicago metro area or the Metro-East St. Louis region and drive a gasoline or hybrid vehicle from model year 1996 or newer, your car most likely needs an Illinois emissions test every two years. The program covers all or part of ten counties, the test itself is free, and you cannot renew your license plates without passing it. Diesel vehicles, motorcycles, fully electric cars, and anything older than model year 1996 are not tested.

Where the Testing Requirement Applies

Illinois does not test statewide. The requirement targets areas that have struggled to meet federal ozone standards under the Clean Air Act.¹ Three counties are covered in full: Cook, DuPage, and Lake. Any address in those counties is inside the testing zone.

Seven more counties are partially covered by zip code: Kane, Kendall, McHenry, Will, Madison, Monroe, and St. Clair.² More rural zip codes in those counties are excluded, and the excluded list has not changed since the program’s current form took effect in 2006. If your zip code is on the line, your registration renewal notice will indicate whether you are due for a test, and the Illinois Air Team website can confirm status by address.

Which Vehicles Are Covered

Testing applies to most gasoline-powered passenger vehicles from model year 1996 or newer. A vehicle does not become subject to testing until the fourth calendar year after its model year, so a 2022 vehicle first tests in 2026.³

After that, the schedule is biennial and tied to the model year. Even model years test in even calendar years; odd model years test in odd years.⁴ You test every other year, not annually.

Hybrids that run on a gasoline engine alongside an electric motor are treated the same as any other gasoline vehicle. They have OBD-II systems and tailpipe emissions, so they follow the standard schedule.³

Vehicles That Are Exempt

Several categories are permanently outside the program, wherever you live in Illinois:

Fully electric vehicles, which have no tailpipe.
Diesel-powered vehicles, which are not part of the current OBD-based program.
Motorcycles, which do not have the standard OBD-II diagnostic port.
Any vehicle from a model year before 1996, which predates the diagnostic technology the test uses.
Vehicles registered with antique, expanded-use antique, custom, or street rod plates, along with all vehicles from model year 1967 or earlier.
Vehicles used exclusively for parades or sporting events, if that is genuinely the only use.

These exemptions are set out at 625 ILCS 5/13C-15.⁴ The renewal notice you receive should already reflect the correct status, but if you believe your vehicle qualifies for an exemption and the notice suggests otherwise, contact the Illinois Air Team or the Illinois EPA before your renewal deadline.

Cost and What to Bring

The mandatory test is free. Drive in, get tested, drive out. If you pass, you are done for two years.

There is a voluntary $20 test some drivers use after repairs to confirm the vehicle will pass, or before selling a car to a buyer in a testing county. It is optional.

When it is time for your mandatory test, the Illinois EPA mails a Vehicle Inspection Notice with a barcode the technician scans. Bring it. If it never arrived or you lost it, you can still be tested using the 17-character VIN visible through the lower driver’s-side windshield and inside the driver’s door jamb. Bring your current registration card as well. Testing station locations and, at some sites, estimated wait times are on the Illinois Air Team website.¹

One practical note. If your battery was recently disconnected or replaced, or you just had repairs done that cleared the check engine light, drive the vehicle for several days under varied conditions before testing. The OBD-II system needs time to complete its internal checks. Without that, the result will be “not ready” rather than pass.

Pass, Fail, and Not Ready

The technician plugs a diagnostic tool into your vehicle’s OBD-II port, and the state’s computer reads the engine control module to check whether the emissions systems are functioning.¹ The check takes a few minutes. If you pass, the result is transmitted to the Secretary of State, and you can renew your plates right away.

There are three ways to fail:⁵

The check engine light is on and the system has stored emissions-related trouble codes. A flashing check engine light means the vehicle needs immediate service; do not drive it to the station.
The OBD system itself is not functioning, so compliance cannot be verified.
The diagnostic link connector is damaged, blocked, or missing, so the test cannot proceed.

A “not ready” result is not a failure. It means the vehicle’s internal monitors have not finished running, usually after a battery disconnect, a recent repair that cleared codes, or too little driving since the reset. Drive under normal conditions for several days and come back.

Options If Your Vehicle Fails

A failed test blocks your registration renewal until the underlying issue is fixed. The Vehicle Inspection Report lists the diagnostic trouble codes that triggered the failure, which gives a mechanic a starting point. After repairs, return for a retest.

Repair Waiver

If you have spent significantly on qualifying emissions repairs and the vehicle still will not pass, Illinois offers a repair waiver. You must have spent at least $1,176 on emissions-related repairs performed by a recognized technician, the repairs must address the specific codes from the initial failure, and you need signed receipts dated within 30 days of your test eligibility date. The emissions control equipment must be present and properly connected, and both the check engine light circuit and the diagnostic port must work; a vehicle that fails because those are broken cannot receive a waiver.⁶

Economic Hardship Extension

If you cannot afford repairs right now, you can apply for a one-year economic hardship extension from your current registration expiration date, which gives you time to save, repair, and either retest or qualify for a waiver. Applications go through the Illinois Air Team online, by email, fax, or mail.⁷

Federal Emissions Warranty

Before you pay for repairs, check whether the vehicle is still under its federal emissions warranty, which is separate from the manufacturer’s bumper-to-bumper warranty. Federal law requires manufacturers to cover major emissions control parts, including catalytic converters, for eight years or 80,000 miles, whichever comes first. Other emissions parts are covered for two years or 24,000 miles.⁸

If your vehicle fails a state emissions test and the failed component is still within warranty, the manufacturer must pay for the repair. A failed state test is enough to trigger the claim, and the manufacturer bears all costs of determining whether the claim is valid.⁹ Bring your failed Vehicle Inspection Report to the dealership.

Consequences of Skipping the Test

Illinois enforces the requirement by blocking registration renewal. Without a pass, waiver, or extension, the Secretary of State will not issue new stickers.¹ Driving on expired registration is a petty offense that carries a fine, and a late renewal adds a separate late registration fee on top. Because the test itself costs nothing and the waiver and extension options exist for the harder cases, the straightforward path is to get it done on schedule.

1
Illinois Environmental Protection Agency. Vehicle Emissions Testing Program
2
Illinois General Assembly. Illinois Vehicle Code 625 ILCS 5/13C-5 – Definitions
3
Illinois Air Team. Does My Vehicle Need to be Tested?
4
FindLaw. Illinois Code 625 5-13C-15 – Inspections
5
Illinois Air Team. FAQs
6
Illinois Air Team. Repair Waiver
7
Illinois Air Team. Economic Hardship Extension
8
eCFR. 40 CFR 85.2103 – Emission Warranty
9
eCFR. 40 CFR 85.2106 – Warranty Claim Procedures