Laws Against Tampering With O2 Sensors

• Altering an O2 sensor may mean your car can no longer pass inspection. Jupiterimages/Photos.com/Getty Images

  Tampering with a vehicle's O2 sensor (otherwise known as oxygen or lambda sensor) in any way that alters its operation and can limit its ability to help control the vehicle's emissions, and thus is illegal in many states with strict emission control standards. Furthermore, the Federal Environmental Protection Agency (EPA) requires manufacturers to produce components in certain ways that make it impossible for owners to tamper inadvertently with the emission control system.

State Anti-Tampering Laws

• Most states have laws against tampering with O2 sensors. For example, part C of California's VC Section 27156 "Gross Polluter Air Pollution Control Device" states that "[n]o person shall install ... any device, apparatus, or mechanism intended for use with, or as a part of, a required motor vehicle pollution control device or system that alters or modifies the original design or performance of the motor vehicle pollution control device or system." This law is comprehensive in that it not only forbids tampering with existing components but also forbids the installation of components that alter an existing emission control system in unapproved ways. California warns that restoring tampered emission control equipment could cost more than the purchase price of the vehicle. Another example is the Ohio EPA's prohibition against the "installation of improper parts or components which defeat, by-pass or render inoperative any emission control part or element of design originally installed or designed into the system by the manufacturer." The Ohio law further stipulates that any person repairing a vehicle that has undergone tampering with must repair the vehicle in such a way as to comply with anti-tampering regulations. In other words, any person completing a tampered emission control element---such as an O2 sensor---is liable for tampering. These state laws reflect the Federal EPA's stipulation that any tampering with a vehicle's emission control system voids the system's warranty.

Federal Regulations

• The Federal EPA states explicitly that any tampering with the emission control system---of which the O2 sensor is just one component---voids the warranty on that emission system and renders the vehicle incapable of passing inspection. The EPA used to allow inspections after alteration of an emission control system to ensure the altered system met emission performance compliance---this provision appeared under Section 203(a)(3) of the Clean Air Act---but revoked this provision after April 1, 2002. As of 2010, the EPA allows modification of emission control system and O2 sensors only as parts of aftermarket conversion system or kits approved by the EPA.

Importing Vehicles

• The U.S. government also requires that all vehicles meet EPA emission standards before being imported into the United States. This requirement implicitly supports the prohibition of tampering or altering emission control systems that meet EPA standards by declaring that any vehicle that the federal government will seize any vehicle falsely labeled as meeting emission control standards.