Vehicle Emissions Testing What to do if you vehicle fails an emissions test. If your vehicle failed the Illinois vehicle emissions test, it needs to be repaired and then retested. These are some of the questions most frequently asked by owners of vehicles that fail the test. If you have any questions not listed here, please speak to the customer service representative at any vehicle emissions test station. I failed only the gas cap portion of the test.
Carbon monoxide is a colorless, odorless toxic gas and is a by-product of incomplete combustion.
Hydrocarbons are unburned fuel vapors. Generally, emission control devices have little Impact on the driveability of a vehicle. Your vehicle may appear to be operating fine but have an emissions system failure. Even the best maintained vehicle might experience these types of failures. A. A dynamometer is a treadmill-like device that allows a vehicle to power a set of rollers, which spin in sync with the vehicle's rotating tires.