Clean Air Car Check

Crown Point - 755 N. Industrial Blvd. [map]
Gary - 3901 W. Fourth Ave. [map]
Griffith - 232 Ivanhoe Court South [map]
Hammond - 1231 Gostlin St. [map]
Hobart - 325 Sullivan St. [map]
Portage - 5777 Melton Rd. [map]
Valparaiso - 2503 Beech St. [map]

Vehicles Due for Testing in 2019
2015 2013 2011 2009 2007 2005
2003 2001 1999 1997 1995 1993
1991 1989 1987 1985 1983 1981
1979 1977        


About Emissions Testing



Depending on the model year of your vehicle, Clean Air Car Check uses different types of emissions tests. All vehicles receive a Gas Cap Pressure Check, which tests to see if a vehicle's gas cap is effectively keeping fuel vapors from escaping. Fuel evaporation is a major cause of ground level smog and a properly functioning gas cap improves gas mileage by preventing fuel waste.

The Second Generation On-Board Diagnostics (OBD II) Test is the most common test procedure and is used to test model year 1996 or newer vehicles. During this simple test, data is downloaded from the vehicle's on-board computer to check for emissions equipment malfunctions. An OBD scanner is attached to a connector typically located under the vehicle's dashboard.

The Inspection and Maintenance (I/M 93) Test is used to test model year 1981 through 1995 or newer vehicles. During this test, an inspector drives the vehicle on a treadmill device called a dynamometer. The test simulates driving on a road. While driving, the vehicle's tailpipe emissions are captured and analyzed to evaluate the effectiveness of the vehicle's emissions control equipment. It is important that a vehicle subject to this type of test has an exhaust system that is intact and leak free. The vehicle also needs properly functioning brakes and should not have any major fluid leaks.

The Single Idle Speed (BAR 90) Test is used to test 1976 to 1980 model year vehicles. A metal probe is inserted into the vehicle's tailpipe while the vehicle idles to sample the exhaust stream. At the same time, a sensor is placed on the hood of the vehicle to measure the engine speed. The probe measures the vehicle's emissions and they are analyzed to determine whether or not the vehicle's emission control equipment is working properly. The vehicle's exhaust system must be intact and leak free.


Motor vehicle manufacturers are required to meet increasingly stringent pollution control standards. Vehicles that are not properly maintained or that have malfunctioning emission control systems often exceed these standards. Vehicle emissions testing is designed to identify such vehicles in order to make necessary repairs to reduce emissions below the applicable pollution control standards. Just over 17% of the vehicles tested fail the initial vehicle emissions inspection. Identifying and repairing these vehicles has reduced ozone precursor emissions by more than 4,000 pounds per summer day. These repairs also improve the vehicle's performance and fuel economy.

The vehicle inspection and maintenance program is a requirement of the 1990 federal Clean Air Act Amendments, and is part of the overall plan to improve air quality by reducing hydrocarbons and nitrogen oxides in Lake and Porter counties. Emission testing improves air quality by ensuring emission controls are working properly. 

Model years 1976 – 1995
Model years 1996 and newer

Model years 1976 – 1995

Fully warm up your vehicle before testing.  If possible, drive your vehicle at highway speeds for at least 15 minutes prior to visiting an inspection station.

Make sure your brakes are in good condition.  Poor brakes are not only a safety hazard, but also make the vehicle very difficult to test on the equipment and may cause the vehicle to be rejected from testing.  If your vehicle is rear wheel drive, you must have functioning rear brakes.

Make sure your front wheel drive vehicle is properly aligned.  Poor front end alignment will make the vehicle difficult to test and may cause the vehicle to be rejected.

Model years 1996 and newer

Address service engine lights promptly. Addressing issues during your warranty period can save you money in the long run. Read your owners manual for specific warranty information.

Don’t clear your codes. Clearing your codes or disconnecting your battery may cause you considerable grief and gas money trying to reset your monitors.

An OBD system is made up of monitors that test different components in the vehicle. Some monitors run all the time (continuous monitors). Others only run at certain times or if special conditions are present (non-continuous monitors). If you clear your codes or disconnect your battery, your non-continuous monitors will no longer be ready and will require a variety of driving to get them to set again. Manufacturers have different drive cycles for their vehicles, and some monitors are more difficult than others to set, particularly some 1996 and 1997 model year vehicles. Monitors that are not ready may cause your vehicle to be rejected from the inspection.

In order to avoid rejection for an inspection-don't clear your codes! If your check engine light is on, find out what Diagnostic Trouble Code (DTC) is causing the light to turn on, fix the problem and drive the vehicle until the light goes off. When the light goes off, you know the problem is fixed. If you are taking your vehicle to a professional repair technician, have the repair technician return your vehicle with the light on. After you take the vehicle through its drive cycle the light should go off and you will know the problem is fixed.



Q. Can I really renew my vehicle's registration at the emissions testing site?

A: Yes! Clean Air Car Check's "Drive-Thru. Renew!" is an officially certified partner of the Indiana Bureau of Motor Vehicles. "Drive-Thru. Renew!" offers partial service license branch transactions, including the sale of temporary permits, registration renewals, new registrations, and will soon add titling to the list of available services. Convenience fees apply.

Q. Why do we need emission testing?

A. The vehicle inspection and maintenance program is a requirement of the 1990 federal Clean Air Act Amendments, and is part of the overall plan to improve air quality by reducing carbon monoxide, hydrocarbons and nitrogen oxides in Lake and Porter counties. Emission testing improves air quality by ensuring that vehicles' emission controls are working properly. This program has contributed to better air quality in Lake and Porter counties.

Q. Why is there a vehicle emissions program in Lake and Porter counties?

A. In the Clean Air Act Amendments of 1977, the United States Environmental Protection Agency designated Lake and Porter counties as nonattainment areas for ozone levels. The counties were reclassified as a severe nonattainment area in the 1990 amendments to the Clean Air Act. This classification requires areas failing to meet the National Ambient Air Quality Standards (NAAQS) for ground-level ozone to develop state implementation plans to attain and maintain the standard. Enhanced vehicle inspection/maintenance testing was put into place as a mandated control measure throughout the Greater Chicago Area, which includes Lake and Porter counties, northeastern Illinois, and southeastern Wisconsin. Though Lake and Porter counties were redesignated to attainment areas in 2010, the vehicle inspection and maintenance program is a key piece of Indiana's plan to prevent backsliding so that the area can remain in attainment.

Q. Why does my vehicle need to be tested?

A. Motor vehicles powered by gasoline are significant contributors to ground level ozone, or smog.  Therefore, testing of these vehicles ensures that emission controls are working properly and, if not working properly, testing ensures that vehicles owners make the appropriate repairs to aid in the reduction of ground level ozone.

Q. How often will my vehicle need to be tested?

A. Your vehicle is scheduled for testing every two years. The four most recent model years are exempt from testing. Odd model year vehicles are tested in odd-numbered years and even model year vehicles are tested in even-numbered years. For example, a 1996 vehicle will be tested in 2000, 2002, 2004, 2006, 2008, and so on. A 1997 vehicle will be tested in 2001, 2003, 2005, 2007, and so on.

Q. When does my vehicle need to be tested?

A. Your vehicle will need to be tested before you can register or renew your vehicle’s registration with the Bureau of Motor Vehicles.

Q. How will I know when I am due for an emissions test?

A. The Indiana Bureau of Motor Vehicles (IBMV) currently notifies all motorists living in Lake and Porter counties when their vehicles are due for testing. If a test is needed, "EMISSION TEST REQUIRED" will be printed on the vehicle registration renewal notice. This notice is mailed approximately two (2) months before the renewal deadline. However, you do not have to wait to receive your notification in the mail before you take your vehicle in for an emissions test. Vehicles can be tested as early as October of the year before it is due for testing.

The present vehicle testing schedule is determined by the month motorists are due to obtain their vehicle registration. The Indiana Bureau of Motor Vehicles vehicle registration renewal schedule is as follows:

2011 Vehicle Registration Renewal Schedule

Who Requires Testing

January 31

Corporate fleets and trust-owned vehicles

February 07

Last names AAAA - ARNN

February 14

Last names ARNO - BATE

February 21

Last names BATF - BLAI

February 28

Last names BLAJ - BRID

March 07

Last names BRIE - BUSD

March 14

Last names BUSE - CHAN

March 21

Last names CHAO - CONN

March 28

Last names CONO - CURL

April 07

Last names CURM - DICE

April 14

Last names DICF - EDDY

April 21

Last names EDEA - FERG

April 28

Last names FERH - FRYA

April 30

Personalized plates

May 07

Last names FRYB - GLOR

May 14

Last names GLOS - GUMZ

May 21

Last names GUNA - HART

May 28

Last names HARU - HILE

June 07

Last names HILF - HUCH

June 14

Last names HUCI - JERR

June 21

Last names JERS - KEEL

June 28

Last names KEEM - KNUD

July 07

Last names KNUE - LAWR

July 14

Last names LAWS - LOPE

July 21

Last names LOPF - MART

July 28

Last names MARU - MCKI

August 07

Last names MCKJ - MILL

August 14

Last names MILM - MUND

August 21

Last names MUNE - NUNG

August 28

Last names NUNH - PATT

September 07

Last names PATU - PONT

September 14

Last names PONU - REDM

September 21

Last names REDN - ROBE

September 28

Last names ROBF - SANC

October 07

Last names SAND - SERM

October 14

Last names SERN - SLON

October 21

Last names SLOO - SPRI

October 28

Last names SPRJ - SUCE

November 07

Last names SUCF - THOP

November 14

Last names THOQ - VANO

November 21

Last names VANP - WALD

November 28

Last names WALE - WATT

December 07

Last names WATU - WILK

December 14

Last names WILL - WRIG

December 21

Last names WRIH - ZZZZ

Q. How much does the emissions test cost?

A. There is no charge for a vehicle emissions test in Indiana.

Q. Where do I take my vehicle for testing?

A. There are seven Clean Air Car Check stations in Northwest Indiana. To determine which station is most convenient for you, call the toll-free Clean Air Car Check hotline at 1-888-240-1684 or see LOCATIONS

Q. How do I know if the used vehicle I purchased requires testing?

A. A vehicle must receive a passing emissions test and provide proof to the Indiana Bureau of Motor Vehicles in order to register and license the vehicle. We advise shoppers in the market for a used vehicle to call the toll-free Clean Air Car Check hotline to check the emissions status of a vehicle before purchasing it. Using the Vehicle Identification Number (VIN), the testing record can be retrieved from the Clean Air Car Check database. If the vehicle was previously tested in an Indiana county requiring emissions testing, we can inform the potential buyer whether or not the vehicle passed the most recent vehicle emissions inspection and when the inspection was conducted.

Q. What vehicles must be tested?

A. In the appropriate model year, passenger vehicles and light-duty trucks with a gross vehicle weight rating (GVWR) of 9,000 pounds or less and an engine displacement of over 200 cubic centimeters must be tested. 

Q. What if I do not comply with the vehicle emissions test?

A. If your vehicle is not in compliance, you will not be able to be register or renew your vehicle's registration with the Indiana Bureau of Motor Vehicles.

Q. What vehicles are exempt?
A. Vehicles which are:

  • The four newest model year vehicles,
  • Model year 1975 and older,
  • Powered by electricity or diesel fuel,
  • Considered show cars and meet established criteria for a Show Car Exemption,
  • Considered kit cars or dune buggies and meet established criteria for Specialty Exemption,
  • Above 9,000 pounds in Gross Vehicle Weight Rating (GVWR) (this is typically located on the vehicle's door jamb),
  • Ceremonial vehicles,
  • Motorcycles,
  • Off-highway construction equipment,
  • Have an engine displacement of less than 200 cubic centimeters,
  • Recreational vehicles (Specifically RVs that are manufactured for the sole purpose of recreation, not vehicles that have been modified for recreational use), and,
  • Registered for farm use only (including tractors).

Q. Why aren’t diesel vehicles’ emissions tested?

A. Diesel exhaust contains relatively low levels of hydrocarbons (HC), carbon monoxide (CO) and nitrogen oxides (NOx), which are the pollutants that react with sunlight to form ozone.

Q. What is my vehicle tested for?

A. The test consists of a gas cap pressure test that checks to see if your gas cap is doing its part to stop evaporative emissions from your gas tank. Inspectors also check under your vehicle to ensure that all the emissions monitoring components are intact. Clean Air Car Check will measure your vehicle for emissions of hydrocarbon (HC), carbon monoxide (CO), and nitrogen oxides (NOx). High emission levels of any of these pollutants indicate that the vehicle is not using fuel efficiently and, as a result, is contributing to poor air quality. For vehicles that are 1996 or newer, the On-Board Diagnostic system provides information about which emission control components are functioning properly.

Q. What effect do hydrocarbons, carbon monoxide and nitrogen oxide have on the environment?

A. Hydrocarbons are unburned gasoline particles that contribute to the formation of ground-level ozone, often referred to as smog. Carbon monoxide is a colorless, odorless gas formed from partially burned fuel that can adversely affect mental function, visual focus, alertness, and can even cause death. Nitrogen oxides, when mixed with other compounds, can contribute to ground- level ozone, acid rain, water quality deterioration, and global warming.

Q. What is ozone?

A. Emissions from gasoline powered vehicles can lead to the formation of ground-level ozone, which can cause eye and throat irritations, respiratory distress, and damage breathing passages, making it difficult for the lungs to work.

Q. How is ozone formed?

A. Ozone is formed near the ground in a photochemical process:

1) Gasoline, paints and solvents evaporate, thereby releasing hydrocarbons.

2) Cars and factories burn fossil fuels, releasing nitrogen oxide and
reactive hydrocarbons.

3) Heat and sunlight trigger a photochemical reaction between these emissions, transforming them into ground-level ozone.


Q. How long will the test take?

A. Once the vehicle enters the first testing position, the three-step test should only take about ten minutes.

Q. Why do some of the lanes at the emissions test site move faster than others?

A. There are many reasons this may occur. Vehicles of different ages are subject to different test procedures. Some test types take longer than others. Fluid leaks, exhaust system problems, idling problems, and insufficient warming of the vehicle's engine can create problems with vehicle testing. Customers without the proper paperwork such as the vehicle's registration or the repair data form can also cause delays. Be assured that we will test your vehicle as quickly as possible.

Q. Why do all of the car accessories have to be turned off?

A. Electrical accessories can interfere with the electronic sensing of the engine speed and can also adversely affect the test results.

Q. How does the test procedure work?

A. For model year 1996 and newer vehicles, a Second Generation On-Board Diagnostics (OBD II) system test is performed. This test does not require the vehicle to be driven on the dynamometer. A scan tool is plugged into the vehicle's OBD connector, which reads the vehicle's computer to check the status of the OBD system.

For model year vehicles 1981 - 1995, the emissions check has three steps. During the first step, an inspector will complete a basic visual inspection for leaking fluids and conditions that may present a safety problem. The inspector will verify the Vehicle Identification Number (VIN) and the Gross Vehicle Weight Rating (GVWR) for trucks or vans. The lane inspector will then inspect for the presence of a catalytic converter and conduct a gas cap pressure check. The motorist will be asked to exit the vehicle and proceed to an enclosed, climate-controlled waiting area.

During the second step, the vehicle is placed on the dynamometer, a treadmill-like device, and secured in place. The lane inspector will enter the vehicle and "drive" the vehicle, following a drive trace projected on a screen in front of the vehicle. "Driving" the vehicle on the dynamometer simulates normal driving situations, including accelerating, decelerating, braking, and stopping. The vehicle is operated between speeds of 0 - 33 mph. Emissions are collected as the vehicle is driven. If a vehicle does not pass the emission test during the first testing cycle, a second-chance test is automatically given. When the test is completed, the lane inspector exits the vehicle. (NOTE: During the second step, a well-maintained vehicle may be able to "fast pass" after the first 30 seconds of the emissions test.)

During the third step, the motorist returns to the vehicle. At this time, the inspector presents the vehicle emission test results.

For model year vehicles 1976 - 1980, the three testing steps are similar except that these vehicles will not be tested on the dynamometer. The vehicle's emissions are checked while the vehicle is idling. The inspector inserts a probe into the vehicle's tailpipe, which collects the emissions for measurement
Regardless of the type of test a vehicle receives, customers may be able to take advantage of Clean Air Car Check's onsite partial license branch services "Drive-Thru. Renew!". If the vehicle fails or rejects, motorists may be eligible to purchase a temporary permit, and if the vehicle passes, "Drive-Thru. Renew!" can renew the vehicle's registration onsite.

Q. What if my vehicle fails the emissions test?

A. The lane inspector will provide you with a Vehicle Inspection Report that states that the vehicle has failed the emissions test. The inspector will also provide additional materials that provide information on how to get your vehicle repaired. More information is available at the customer service entrance of the Clean Air Car Check station or by calling the toll-free hotline at 1-888-240-1684.

Q. Where should I take my vehicle for repairs?

A. Any repair facility may repair your vehicle's emission system. However, in order to qualify for a waiver for a vehicle that is model year 1981 or newer, should that be necessary, the repairs must have been completed by an Indiana Certified Emission Repair Technician (ICERT) Facility.  A list of ICERT shops will be provided to you before you leave the test site if your vehicle fails.

Before choosing a shop, informed customers should ask:

  • Do you have a gas emissions analyzer that is in good working order?
  • Do you guarantee your repair work?
  • Do you have a refund policy for guaranteed work?
If you have any other questions, please call the Clean Air Car Check toll-free hotline at 1-888-240-1684.