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Anti-Tampering Program

The Ohio Revised Code 3704.16, effective September 27, 1993, protects consumers from being sold tampered vehicles. It was amended on June 28, 1993, by Senate Bill 18. The law also enhanced Ohio EPA's authority to enforce existing tampering related prohibitions, such as selling or installing a device on a vehicle that would damage or bypass any emission control system. Vehicles that are sold, or title otherwise transferred, under the condition of "as is" still have to comply with the anti-tampering law.     

Anti-tampering fact sheets


Additional questions? Call 330-963-3349 or 614-644-3059

What is vehicle tampering?

According to Ohio Revised Code Section 3704.16, tampering means "to remove permanently, bypass, defeat, or render inoperative, in whole or in part, any emission control system that is installed on or in a motor vehicle." Tampering includes acts such as: removing the catalytic converter from a vehicle and installing a straight pipe; removing the substrate from inside the catalytic converter ("cleaning" it out); removing an air pump or disabling the air pump by removing the air pump belt; or installing a nonstandard thermostatic air cleaner. 

Just what is illegal in Ohio?

Under state law, it is illegal to knowingly sell, lease, rent or operate a vehicle in a tampered condition. Removing a pollution control device from a vehicle is illegal. Likewise, selling or installing a device that would hamper the effectiveness of any vehicle pollution control system is prohibited. Individuals, as well as car dealerships, muffler shops, and repair facilities, are prohibited from tampering with a motor vehicle. 

What remedies are available to me if I purchase a tampered vehicle?

If you purchased a tampered vehicle, you may take independent legal action to rescind the sale and recover damages from the seller. In addition, you may file a complaint with the Mobile Sources Section of the Ohio EPA. You may call 330-963-4479 to make a complaint. If the vehicle was purchased from a dealer and an Ohio EPA investigation determines that further violations of the anti-tampering law have occurred, Ohio EPA can take an enforcement action against the dealer. 

What should I look for when buying a used vehicle?

Before buying the vehicle, ask the seller if the vehicle meets all federal and state emission system tampering laws. You should then look under the hood of the car for the Vehicle Emissions Control Information (VECI) label. This label identifies most of the emission control systems that were installed on the vehicle when it was manufactured. Next to the VECI label should be a routing diagram that shows where on the engine the emission control devices are located. If the seller is familiar with the workings of a vehicle engine, have him or her show you all of the devices, including the catalytic converter. If the seller is not familiar with the vehicle's engine, ask if the vehicle can be driven to a repair facility so it can be inspected. It is a good practice to take a used vehicle you are considering buying to a repair technician you trust. You can go to the following website to see what a VECI label looks like: 


Soon after I purchased a vehicle, the catalytic converter quit working. Was it illegal for the seller to allow me to purchase the vehicle?

Probably not. If the converter was present and properly connected when the vehicle was sold to you, it was not tampered but, most likely defective or poorly maintained. Poor maintenance can result in corroded exhaust systems and converters, deteriorated hot air tubes, as well as clogged air filters. Although poor maintenance does affect your vehicle's emission system, it is not considered tampering. Tampering involves acts such as willfully removing the converter, air pump, computer controls, etc., plugging the vacuum line to the exhaust gas recirculation valve, or installing a dual exhaust system on a vehicle originally designed for single exhaust that had no option for dual exhaust. If the converter is defective, you may be entitled to free warranty repairs. You may find information in the vehicle's manual in the Vehicle Warranty Booklet or contact Ohio EPA's Mobile Sources Section at 614-644-3059 or 330-963-4479 for additional information about the defective emission parts warranty. 

Can I trade in my tampered vehicle for a new car?

When you trade in a vehicle, you are actually selling the vehicle to a dealer. Trading in a tampered vehicle, therefore, violates the anti-tampering law. Under this scenario, a judgment could be made requiring the rescission of the sale and possibly requiring you to pay damages to the dealer. If the vehicle dealer sells that vehicle to someone else in the same tampered condition, the dealer, not you, would be held liable for the sale to the consumer. This does not keep the dealer from seeking legal action against you. 

Before I knew my used vehicle was tampered, I spent a good deal of money having repairs performed. Can I recover any of the money?

The person that you purchased the vehicle from should be allowed the opportunity to repair the vehicle to an "as manufactured" condition or allow you to return the vehicle for a full refund. Damage amounts may be awarded by a judge if the buyer decides to file a motion in court. If a judge decides that a seller knowingly sold the vehicle in a tampered condition, the seller may be required to repair the vehicle so that it conforms to the U.S. EPA-certified vehicle configuration of that model year or newer. 

What problems might I encounter by driving a tampered vehicle?

Some motorists will remove or disconnect an emissions device believing that removing or disconnecting the device will increase gas mileage or have no effect on a vehicle. But tampering will affect vehicle performance in a negative way. Today's vehicles are sophisticated machines with well-integrated systems. Disabling or removing any emission control system can result in decreased performance, poor fuel economy, greater damage to other associated systems and, in extreme cases, an inoperable vehicle.

Furthermore, if you live in a county that has an automobile emissions testing program, you may have difficulty registering a tampered vehicle. Depending on the degree of tampering, a vehicle can fail the inspection and the owner can incur potentially high repair costs in order to pass inspection. Vehicles are required to pass inspection before they are registered.

Perhaps, the best reason not to tamper with your vehicle's emission control systems is that doing so adds pollution to the air. Well-maintained vehicles that are kept in their original configuration emit a small amount of pollutants. Tampered vehicles can emit well over 100 times that amount. When our vehicles are polluting as little as possible, we will contribute to improving the air quality.

What remedies are available if I purchase a tampered vehicle from a wholesaler or an auctioneer?

If you purchased a tampered vehicle from a wholesaler in Ohio, you may take independent legal action to rescind the sale and/or recover damages from the seller. In addition, you may file a complaint with the Ohio EPA Mobile Sources Section at 614-644-3059 or 330-963-4479. If an Ohio EPA investigation determines that further anti-tampering violations have occurred, Ohio EPA can take enforcement action against the wholesaler.

If you purchased a vehicle from an auction, you cannot seek a recission or damages from the auctioneer because the auctioneer does not take title to the vehicle. A recission or damages may be sought from the previous owner if the vehicle was titled in Ohio at the time of the purchase.

Is there a special procedure I should follow if I want to sell a tampered vehicle to a salvage dealer for parts?

There is no special procedure if the dealer is a licensed  salvage dealer. The Bureau of Motor Vehicles only allows individuals with salvage dealer licenses to apply for and receive salvage certificates of title. Vehicles with salvage certificates of title are exempt from the provisions on the anti-tampering law. Be sure that the dealer to whom you sell the tampered vehicle has a salvage dealer license and that he or she intends to obtain a salvage certificate of title for the vehicle (It is a good idea to get this in writing.). Following the above procedure will make it clear that you intend to comply with the anti-tampering law. 

Is it illegal to sell high-performance vehicles or race vehicles?

Vehicles that are used solely for racing (meaning they are only driven on a race track and towed or transported on a trailer to race tracks) may be sold in a modified condition if the new owner intends to use the vehicle for racing. It is a good idea to have the buyer sign a statement agreeing that he or she intends to drive the vehicle only on race courses.

Vehicles which have been modified and are in a tampered condition cannot be sold if they are driven on the roadways, even if only for a short distance. This type of vehicle should be returned to manufacturer's specifications before selling or operating it.

Should I take a tampered vehicle as a customer trade-in for a new vehicle?

No. The trade-in transaction is considered a sale, and this act would violate the anti-tampering law by the owner of the vehicle. If a customer offers you a tampered vehicle in trade, you should tell the customer that the tampered emissions systems must be repaired prior to accepting the vehicle. You may offer to repair the vehicle, if you have the ability to do the necessary repairs before the sale or transfer of the vehicle.  The repair costs may be negotiated as part of the trade-in agreement.

How can I protect myself from a customer falsely accusing me of selling a tampered vehicle?

In Ohio Revised Code Section 3704.162 (C) (1), the law allows reasonable reimbursement of attorney's fees if the court finds the complainant has brought or maintained a groundless action. Reimbursement of attorney fees also may be awarded if the action was filed in bad faith or if the complainant has tampered with the vehicle after the sale. To protect yourself from the ramifications of selling, or being accused of selling a tampered vehicle, you may want to develop a checklist of emission control systems that you and the consumer can review prior to vehicle purchase.

There are at least three companies in the U.S. that produce manuals containing emission control tables for most makes and models of foreign and domestic vehicles. These manuals are good resources for repair technicians and vehicle dealers concerned about the federal and state anti-tampering laws. You may contact Ohio EPA's Mobile Sources Section at 330-963-4479 for further information about these manuals.


I sold a customer a used vehicle and a few days later the air pump belt fell off. Am I guilty of selling a tampered vehicle?

A deteriorated air pump belt is considered a poorly maintained item and not a tampered item because the belt was present at the time of sale, even though it probably was in poor condition. The new owner is responsible for replacement cost of this item, if it is not under warranty.

Additional questions? Call 330-963-4479