Emission Control and Air Pollution Module

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Day 5: How Can I Pass my Emissions Test?

This contains USEFUL INFORMATION about vehicle emission testing in Illinois, and what you can do to make sure you can pass your emission test!

Vehicle Emissions Testing In Illinois

The Illinois vehicle emissions test checks whether or not the emission control system on your motor vehicle is working properly. Motor vehicle manufacturers are required to meet increasingly stringent pollution standards, but vehicles that are not properly maintained or that have malfunctioning emission control systems often exceed these standards. Vehicle emissions tests identify such vehicles, and repairs are then required to reduce the emissions which cause pollution. These repairs help clean the air while improving the vehicle's performance and fuel economy.

The following figure shows basic controls for exhaust and evaporative emissions:



Your vehicle is scheduled for testing every two years: even model year vehicles are tested in even years, and odd model year vehicles are tested in odd years. A tailpipe exhaust sample is taken at low idle (engine speed between 350 rpm and 1300 rpm) and analyzed for concentrations of hydrocarbons and carbon monoxide. The "black bag" that the lane operator may use on your hood is one of three different electronic sensors used to determine engine speed.

<>Vehicles failing the emissions test must be repaired, then retested. If your vehicle failed the emissions test, we recommend that you have the vehicle repaired by a qualified technician who is experienced in the diagnosis and repair of emission control systems. If a vehicle cannot pass the emissions test, a waiver may be available after the emission control system has been inspected and the required repairs and adjustments have been completed. All emission control components must be present and functioning, but major engine overhaul is not required.

If Your Car Just Failed An Emissions Test

If you want more information about what you can do if your car just failed an emissions test go to the following homepage:

For information about Vehicle Inspection & Maintenance go to the following homepage:



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