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Driver guide · Michigan City Ford · Michigan City, IN
Indiana Emissions Testing: Clean Air Car Check Explained
If your vehicle is registered in Lake or Porter County, Indiana requires an emissions test every other year through the Clean Air Car Check program. Here is who must test and when, the three kinds of tests, why a car fails or is rejected, and the exemptions and waivers, for drivers in Northwest Indiana.
2counties where Indiana requires testing: Lake and Porter (IDEM)
Every 2 yearstest cycle; even model years in even years (Clean Air Car Check)
4newest model years exempt (Clean Air Car Check)
Oct. 1of the year before it is due: the earliest test date (Clean Air Car Check)
The short answer
Gasoline cars and light trucks up to 9,000 pounds GVWR that are registered in Lake or Porter County must pass a Clean Air Car Check emissions test every other year: even model years in even calendar years, odd model years in odd years. The four newest model years are exempt. On 1996 and newer vehicles, a lit Check Engine light means a failed test.
Who needs an Indiana emissions test
Indiana's vehicle emissions testing requirements apply in Lake and Porter counties, the Indiana Department of Environmental Management (IDEM) says. The program, called Clean Air Car Check, identifies vehicles that emit high levels of nitrogen oxides or volatile organic compounds and makes sure faulty emissions systems are repaired, to cut ground-level ozone in Northwest Indiana.
Per Clean Air Car Check, gasoline-powered passenger vehicles and light duty trucks with a Gross Vehicle Weight Rating (GVWR) of 9,000 pounds or less that are being registered in Lake or Porter County must pass an emissions test every other year. The program is a requirement of the 1990 federal Clean Air Act Amendments.
From IDEM, Vehicle Emissions Testing Program, and Clean Air Car Check, About Emissions Testing, read October 29, 2026. This page is a summary, not legal advice.
When your vehicle is due
Clean Air Car Check's rules for timing:
Even and odd years
Even model year vehicles test in even calendar years. Odd model year vehicles are due in odd calendar years.
Newest vehicles skip it
There is an exemption for the four newest model years.
Test early
A vehicle can be tested as early as October 1 of the year before it is due. You do not need to wait for the renewal notice; just test before your registration expires.
Due in 2026
The program lists model years 2022, 2020, 2018 and every even model year back to 1976 as due for testing in 2026.
From Clean Air Car Check, home page and About Emissions Testing, read October 29, 2026. Testing early gives you more time to make repairs if needed.
The three Clean Air Car Check test types
Every vehicle also gets a gas cap pressure check. The main test depends on the model year:
| Model years | Test | What happens |
|---|---|---|
| 1996 and newer | OBD II test | Data is downloaded from the vehicle's on-board computer through a connector usually under the dashboard, to check for emissions equipment malfunctions. |
| 1981 to 1995 | I/M 93 test | An inspector drives the vehicle on a dynamometer while tailpipe emissions are captured and analyzed. The exhaust must be leak free, and the brakes must work. |
| 1976 to 1980 | Single idle speed (BAR 90) test | A probe samples the exhaust while the engine idles and a sensor measures engine speed. |
| All | Gas cap pressure check | Tests whether the gas cap keeps fuel vapors from escaping. |
From Clean Air Car Check, About Emissions Testing, read October 29, 2026.
Fail vs. reject on 1996 and newer vehicles
Per Clean Air Car Check:
FAIL: trouble codes stored
A vehicle with one or more diagnostic trouble codes stored in its on-board computer fails. If your Check Engine light is on, your vehicle will fail.
FAIL: light not working
Part of the inspection makes sure the Check Engine light works. A vehicle fails if the light is not operable.
REJECT: monitors not ready
Readiness monitors must report Complete; only the EVAP monitor may be Incomplete. Common causes include low battery voltage, codes cleared with a scan tool, or a pending code.
Don't clear codes
Clearing codes or disconnecting the battery resets the monitors, and it takes a variety of driving to set them again. Monitors that are not ready can get the vehicle rejected.
From Clean Air Car Check, Failure Information and About Emissions Testing, read October 29, 2026.
Repairs and retests
The Vehicle Inspection Report (VIR) explains why a vehicle failed. Clean Air Car Check says the person who made the repairs must complete and sign the back of the VIR, including the repair facility's federal tax ID number, before a retest; if it is not filled out, the vehicle may not be tested. The program publishes a list of Indiana State Certified Emissions Repair Facilities.
If a mechanic clears trouble codes by resetting the on-board computer, or after a REJECT result, Clean Air Car Check recommends driving three to five days with a mix of city and highway driving before returning, because a retest too soon may be rejected. If you are worried your vehicle will fail, it suggests testing before making repairs, since only repairs made after a failing test count toward a waiver.
Need more time? A vehicle with a fail or reject result may be eligible for a 30-day temporary permit sold at the test station; the registered owner must be present. Clean Air Car Check notes that the Indiana BMV allows only two 30-day temporary permits in a 12-month period, with a failed test between them. Clean Air Car Check is also a BMV service provider, so you can renew a registration there; convenience fees apply.
From Clean Air Car Check, Failure Information, About Emissions Testing and Indiana BMV Services, read October 29, 2026.
Exemptions
Clean Air Car Check lists these exemptions:
| Exemption | Who qualifies |
|---|---|
| Electric vehicle | Fully electric vehicles are exempt; apply with the online form. |
| Diesel or alternative fuel | Vehicles fueled by diesel, propane, natural gas, CNG or electricity. They must be presented at a station during their test cycle. Gasoline hybrids still test. |
| Antique | Vehicles at least 25 years old with collectible or classic car insurance, or that pass an equipment inspection at a station; limited to 3,000 miles per calendar year to renew. |
| Show car | Vehicles used mainly for shows, driven no more than 3,000 miles a year, entered in at least two shows a year and kept in show condition; must be presented at a station. |
| Specialty | Strictly recreational vehicles such as dune buggies and kit cars, driven minimally on the road; must be presented at a station. |
From Clean Air Car Check, Extensions, Exemptions & Waivers, read October 29, 2026.
Waivers and out-of-state vehicles
A waiver is a temporary extension that gives the owner extra time for additional repairs before the next time the vehicle is due. Clean Air Car Check says only one waiver, valid for one test cycle, can be issued in the lifetime of a vehicle, and the vehicle must meet every requirement in the program's waiver eligibility chart. Bring the original receipts for parts and repairs to station management; a diagnostic technician verifies the repairs before a waiver is approved.
If your Indiana-registered vehicle is more than 300 miles from a Clean Air Car Check station, you can apply for an Out of State Extension with proof of the vehicle's location and a $40 processing fee ($10 more for rush processing). The test is due once the vehicle returns to Indiana.
From Clean Air Car Check, Extensions, Exemptions & Waivers and About Emissions Testing, read October 29, 2026.
Before your test: service at Michigan City Ford
The Works® at Michigan City Ford 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 before your emissions test, ask our service team about it when you book.
Schedule service online and see our service specials first. Michigan City Ford is at 3930 Franklin St. in Michigan City. Get directions.
Michigan City Ford service hours
| Days | Hours |
|---|---|
| Mon-Fri | 7:30 a.m.-5:30 p.m. |
| Sat | 8 a.m.-3 p.m. |
| Sun | closed |
From Michigan City Ford's website, October 29, 2026. Holiday hours can differ.
Indiana emissions testing FAQ
Which Indiana counties require emissions testing?
Lake and Porter counties. IDEM says Indiana's vehicle emissions testing requirements apply in Lake and Porter counties, and the program is called Clean Air Car Check.
How often do I need an emissions test in Lake or Porter County?
Every other year. Clean Air Car Check says gasoline-powered passenger vehicles and light duty trucks with a GVWR of 9,000 pounds or less that are registered in Lake or Porter County must pass a test every other year. Even model years test in even calendar years and odd model years in odd calendar years. The four newest model years are exempt.
When can I get my emissions test done?
Early. Clean Air Car Check says a vehicle can be tested as early as October 1 of the year before it is due, and you do not have to wait for your registration renewal notice.
Will my car fail if the check engine light is on?
Yes, for 1996 and newer vehicles. Clean Air Car Check says that if your Check Engine light is on, your vehicle will fail the inspection. A vehicle also fails if the Check Engine light does not work.
What is the difference between FAIL and REJECT?
On a 1996 or newer vehicle, a FAIL can mean one or more diagnostic trouble codes are stored or the Check Engine light does not work. A REJECT means readiness monitors are not complete, for example after low battery voltage or codes cleared with a scan tool. For a reject, Clean Air Car Check recommends three to five days of mixed city and highway driving before a retest.
Are electric and diesel vehicles exempt?
Yes. Clean Air Car Check says fully electric vehicles are exempt, and vehicles fueled by something other than gasoline, including diesel, propane, natural gas, CNG or electricity, receive an Alternative Fuel Exemption; they must be presented at a station during their test cycle. A gasoline hybrid still needs a test.
What does The Works at Michigan City Ford include?
The Works® at Michigan City Ford 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.
Get ready for your emissions test
Book The Works, which includes a Multi-Point Inspection and battery test, at Michigan City Ford.
Sources
Emissions testing rules are from the Indiana Department of Environmental Management and its Clean Air Car Check program site, read October 29, 2026. Rules and fees change; this page is a plain-language summary, not legal advice. Service details, address and hours are from Michigan City Ford's own website, checked the same day. Photo is illustrative.
- Vehicle Emissions Testing Program (Lake and Porter counties), Indiana Department of Environmental Management, read October 29, 2026
- Clean Air Car Check home (test stations, model years due in 2026), Clean Air Car Check, read October 29, 2026
- About Emissions Testing (who tests, test types, testing tips, out of state), Clean Air Car Check, read October 29, 2026
- Failure Information (fail and reject results, repairs and retests), Clean Air Car Check, read October 29, 2026
- Extensions, Exemptions & Waivers, Clean Air Car Check, read October 29, 2026
- Indiana BMV Services (registration, 30-day temporary permits), Clean Air Car Check, read October 29, 2026
- General service: The Works, Michigan City Ford, October 29, 2026
- Address and service hours (structured data), Michigan City Ford, October 29, 2026