Vehicle tampering: Consumers

Emission control equipment installed on motor vehicles and engines is there to protect your health by reducing air pollution. You can help this equipment keep our air clean by following these general guidelines:

  • When buying a used vehicle, ask the seller to demonstrate that all the pollution control equipment is present and working
  • Keep your vehicle’s emission controls intact and operating effectively
  • Never deviate from the manufacturer’s specifications for your car’s engine. (If you do not know what the proper specifications are, consult a reputable automotive technician or an authorized manufacturer’s representative.)
  • Help your vehicle’s pollution-control equipment remain effective by following a regular maintenance and repair schedule  

Detecting vehicle tampering

Catalytic converterOne of the most important pollution control devices on your car is the catalytic converter, which controls the pollution from the vehicle’s tailpipe. The catalytic converter burns fuel that was not completely consumed in the engine and, therefore, reduces the amount of pollutants emitted.

When looking under your vehicle, you should be able to see two “swellings” in the long series of pipes that make up the exhaust system. On most vehicles, the closest to the engine is the catalytic converter. The other is the muffler, which reduces engine noise. If your engine is not running loudly and only one device is present, it is possible the catalytic converter has been removed.

Other equipment, such as the air pump, exhaust gas recirculation (EGR) valve and thermostatic air cleaner also help reduce emissions by promoting a cleaner, more complete combustion. The vehicle’s emission control equipment label, usually found under the hood, can also tell you the pollution control equipment that your vehicle should have.

If a tampered vehicle has been purchased

  1. Document the events that have occurred since you bought the vehicle 
  2. Do not attempt to repair the vehicle. The previous owner may be willing to resolve the issue, but could become hesitant if you present a repair bill for work that the seller could have had done at a lower cost
  3. Have a qualified automotive technician make a complete, itemized list of missing or altered control devices
  4. Contact the seller to determine if the vehicle should be returned for a refund or if the seller will repair the vehicle at no cost (Keep in mind that even vehicles purchased without warranties (“as is”) must still comply with the federal and state tampering laws)
  5. If an agreement cannot be reached, write a letter to the seller that briefly describes the situation, set a date by which you want a response, and mail your letter with a certified return receipt. For information on how to file a complaint in Small Claims Court, contact your county court offices
  6. Notify the MPCA of a repair shop or dealership that has tampered with vehicles by filling out our Online Complaint Form

If you wish to pursue legal action, contact your county court office for information on how to file a complaint. MPCA can not take legal action on behalf of either party.