Driver guide · Ford of Peoria · Peoria, IL
Illinois Emissions Testing: Who Needs It and How It Works
Illinois requires vehicle emissions tests in the Chicago and Metro-East St. Louis areas, and a vehicle that is due must pass or otherwise comply before its license plates can be renewed. Here is which vehicles are tested, how often, how the OBD test works, why a lit check engine light with stored trouble codes means a fail, and what happens if a vehicle fails, for drivers around Peoria and anyone moving to or from a testing area.
The short answer
Most 1996 and newer gasoline cars and light trucks registered in the Chicago or Metro-East St. Louis testing areas need an emissions test once they are four years old, then every two years, in the month their plates expire. The test reads the on-board diagnostics (OBD) computer: a lit check engine light with stored trouble codes is a fail. Your Secretary of State renewal notice says whether a test is required.
Who needs an emissions test in Illinois
The federal Clean Air Act requires vehicle emissions inspection programs in large urbanized areas that do not meet the national air quality standard for ozone, and the Illinois Vehicle Emissions Inspection Law of 2005 (625 ILCS 5/13C) requires a program in those areas of Illinois. The Illinois EPA says air pollution levels in the Chicago and Metro-East St. Louis areas still exceed the ozone standard, so the program operates there.
Most 1996 and newer gasoline-powered passenger vehicles are subject to inspection after they are four years old. The inspection month coincides with the expiration date of the vehicle's license plate, and typically even model-year vehicles are inspected in even years and odd model-year vehicles in odd years. The Illinois Air Team's example: a 2021 vehicle is tested for the first time in 2025. Testing also covers 2007 and newer heavy-duty vehicles with a gross vehicle weight rating between 8,501 and 14,000 pounds.
From the Illinois EPA Vehicle Emissions Testing page and the Illinois Air Team page Does My Vehicle Need to be Tested?, read October 28, 2026. This page is a summary, not legal advice.
Vehicles that are not emissions tested
The Illinois Air Team lists these vehicles as not subject to emissions testing:
Diesel and all-electric
Diesel-powered vehicles and vehicles powered exclusively by electricity. Hybrid-electric vehicles are still tested.
Motorcycles
Motorcycles, motor-driven cycles and motorized pedal-cycles.
Older and special vehicles
Antique and expanded-use antique vehicles, custom vehicles, street rods, and vehicles of model year 1967 or before.
Farm vehicles
Farm vehicles and implements of husbandry.
Heavier vehicles
Model year 2006 or earlier vehicles rated between 8,501 and 14,000 pounds GVWR, and any vehicle rated over 14,000 pounds.
Others
Vehicles not subject to registration, vehicles registered in and complying with another state's emissions program, vehicles with a Junking Certificate, and government implements of warfare.
From the Illinois Air Team, Does My Vehicle Need to be Tested? and Frequently Asked Questions, read October 28, 2026.
How the Illinois OBD emissions test works
For most 1996 and newer passenger cars and light-duty trucks, including vans, SUVs and hybrids, Illinois uses an On-Board Diagnostics (OBD) test instead of a tailpipe and gas cap test. A scan tool is connected to the vehicle's on-board computer to check the OBD system status (readiness checks), whether the Malfunction Indicator Lamp is commanded on, and any stored diagnostic trouble codes.
A vehicle passes if the OBD system is working, all required emissions readiness checks are complete and the Malfunction Indicator Lamp is not commanded on. It fails if the lamp is commanded on and trouble codes are present, or if the OBD system is inoperable or the connector is missing, damaged or inaccessible. The Air Team notes that a transmission code that turns the lamp on is emissions related.
Before you go, remove any device plugged into the OBD connector, such as an insurance dongle, GPS tracker or scan tool (vehicles with a BAIID connected there are tested without removing it). Testing is free and needs no appointment, and anyone can bring the vehicle in; the registered owner does not have to be there. Drivers must step out of the vehicle during the test.
From the Illinois Air Team, About Vehicle Emissions Testing and Frequently Asked Questions, and the Illinois EPA vehicle emissions testing FAQ, read October 28, 2026.
If your vehicle fails or is rejected
What the Illinois Air Team says happens next:
You get a report
The inspector gives you a Vehicle Inspection Report with the detailed results, a Repair Shop Report listing repair facilities, and a Repair Data Form.
Repair, then retest
A failing vehicle must be repaired and return for a retest, and it must pass before its registration expires. The Illinois EPA recommends a technician trained and experienced in emissions diagnosis and repair.
Repair Data Form
The repair technician should submit the Repair Data Form online for you. If not, bring it to the retest.
Rejected is not failed
Common reasons for a rejection: OBD monitors not ready, an incomplete Repair Data Form, a vehicle not subject to testing, the wrong vehicle or a vehicle brought in too early. Rejects do not count as tests.
Waivers and extensions
A vehicle tested at least twice and repaired that still fails may qualify for a Repair Waiver. An owner who cannot afford needed repairs may apply for a one-year Economic Hardship Extension.
From the Illinois Air Team, Frequently Asked Questions and Waivers, Exemptions & Extensions, read October 28, 2026.
Test notices and license plate renewal
A test notice is mailed up to four months before your license plates expire. The Illinois EPA urges motorists to test several weeks before plate expiration so there is time to complete repairs and a retest if needed.
The Illinois EPA enforces the program with the Illinois Secretary of State, which denies plate renewals to vehicles that are not in compliance. The Secretary of State's renewal notices, paper or emailed, state whether compliance with the Vehicle Emissions Inspection Law is required before the registration can be renewed. The Illinois Air Team also has a Vehicle Eligibility Check tool that tells you, by VIN or plate number, when your vehicle is due.
From the Illinois EPA Vehicle Emissions Testing page and FAQ, and the Illinois Air Team, About Vehicle Emissions Testing, read October 28, 2026.
Moving, selling and out-of-area vehicles
If you move, update the address on your driver's license and vehicle registration with the Illinois Secretary of State. Once your record is updated, you only receive a test notice if your new address is inside the testing area. A vehicle may also need a test when it is newly registered in a testing area. If you no longer own a vehicle, tell the Secretary of State so the test notices stop.
A vehicle located and primarily used outside the Illinois testing area, in a state or county without emissions testing, may qualify for an Out of Area Exemption. The owner applies with an official document showing the owner's name and address, generally no more than three months old.
From the Illinois Air Team, Frequently Asked Questions and Out of Area Exemption, read October 28, 2026.
Check engine light on? Service at Ford of Peoria
The Works® at Ford of Peoria includes a synthetic blend oil change, tire rotation and pressure check, brake inspection, Multi-Point Inspection, fluid top-off, battery test, and a filter, belts and hoses check. If your check engine light is on, schedule a visit before your test is due.
Schedule service online and see our service specials first. Ford of Peoria is at 2211 W. Pioneer Pkwy. in Peoria. Get directions.
Ford of Peoria service hours
| Days | Hours |
|---|---|
| Mon-Fri | 7 a.m.-5:30 p.m. |
| Sat | 8 a.m.-noon |
| Sun | closed |
From Ford of Peoria's website, October 28, 2026. Holiday hours can differ.
Illinois emissions testing FAQ
Which vehicles need an emissions test in Illinois?
Most 1996 and newer gasoline-powered passenger vehicles are subject to testing after they are four years old, the Illinois EPA says. Even model-year vehicles are typically tested in even years and odd model-year vehicles in odd years, and the testing month matches the month your license plate registration expires.
Is emissions testing required everywhere in Illinois?
No. The Illinois EPA describes the program as covering the Chicago and Metro-East St. Louis areas, where ozone levels still exceed the federal standard. Your Illinois Secretary of State license plate renewal notice states whether emissions compliance is required before your registration can be renewed.
How often do you need an emissions test in Illinois?
Every two years once testing starts. The Illinois Air Team gives the example of a 2009 vehicle tested first in 2013, then in 2015, 2017 and so on.
Will my car fail if the check engine light is on?
Yes. The Illinois Air Team says vehicles fail the OBD test if the Malfunction Indicator Lamp (the check engine light) is commanded on and diagnostic trouble codes are present. Vehicles also fail if the OBD system is inoperable or the OBD connector is missing, damaged or inaccessible.
How much does an Illinois emissions test cost?
The required test costs nothing. The Illinois EPA says testing is free, whether at a high-capacity test station or one of the newer options, and no appointment is needed.
Are electric and diesel vehicles exempt?
Yes. Diesel-powered vehicles and vehicles powered exclusively by electricity are on the Illinois Air Team list of vehicles not subject to emissions testing. Hybrid-electric vehicles are tested.
What does The Works at Ford of Peoria include?
The Works® at Ford of Peoria includes a synthetic blend oil change, tire rotation and pressure check, brake inspection, Multi-Point Inspection, fluid top-off, battery test, and a filter, belts and hoses check.
Book a checkup before your test
Book The Works, which includes a Multi-Point Inspection, battery test and fluid top-off, at Ford of Peoria.
Sources
Emissions testing rules are from the Illinois EPA and the Illinois Air Team (the Illinois EPA's testing program website), read October 28, 2026. Rules change; this page is a plain-language summary, not legal advice. Service details, address and hours are from Ford of Peoria's own website, checked the same day. Photo is illustrative.
- Vehicle Emissions Testing (program areas, eligibility, enforcement), Illinois EPA, read October 28, 2026
- Vehicle Emissions Test Program FAQ (free testing, test notices), Illinois EPA, read October 28, 2026
- Does My Vehicle Need to be Tested? (eligibility, vehicles not tested), Illinois Air Team, read October 28, 2026
- About Vehicle Emissions Testing (OBD test, plate renewal), Illinois Air Team, read October 28, 2026
- Frequently Asked Questions (failing, rejections, moving), Illinois Air Team, read October 28, 2026
- Waivers, Exemptions & Extensions, Illinois Air Team, read October 28, 2026
- Out of Area Exemption, Illinois Air Team, read October 28, 2026
- General service: The Works, Ford of Peoria, October 28, 2026
- Address and service hours (structured data), Ford of Peoria, October 28, 2026