Maryland Anti-Tampering Program

It is illegal to tamper with emissions systems for gas and diesel vehicles. Motor vehicles contribute to nearly half of the air pollution in the United States. These pollutants are linked to a variety of problems, including decreased lung function, aggravated asthma, heart disease, and premature death in people with heart or lung disease. Tampering can make a vehicle emit hundreds to thousands of times more pollution than it should, voids your warranty, and makes the vehicle illegal to sell or trade-in.
For more information, please email: mde.tampering@maryland.gov.​​
 

 Tampering FAQs

 

What is tampering?

 

​If you remove, disconnect, detach, deactivate, alter, modify, reprogram, or make less effective any emission control device installed by the manufacturer, or use less effective replacement parts, you have committed the act of tampering. This includes installing replacement parts that don’t meet the manufacturers’ specifications, reprogramming computer components or installing performance chips to bypass or defeat factory settings. ​

How does tampering affect health?

 

​Tampering with your emissions control systems leads to much higher levels of nitrogen oxides (known as NOx), soot, carbon monoxide, and hydrocarbons. These pollutants contribute to a variety of public health problems, such as premature death in people with heart or lung disease, heart attacks, irregular heartbeat, aggravated asthma, decreased lung function, and respiratory symptoms such as irritation of the airways, coughing, or difficulty breathing. NOx reacts with sunlight to cause ground-level ozone pollution known as smog, so discomfort and illness may increase, and visibility become more limited, in the summer with vacation travel and people spending more time out¬side.​

How does tampering affect the environment?

 

​Tampering can make a vehicle emit hundreds to thousands of times more pollution than it should. EPA has found that controls on over 500,000 diesel pickup trucks, or about 13% of those registered that were originally certified with emissions controls, have been fully removed or deleted through tampering. The excess NOx emissions produced by these vehicles is the same as adding 9 million extra trucks to our roads and interfere with Maryland’s efforts to keep the air clean statewide.​

 

 Consumer FAQs

 

Is tampering with a vehicle legal?

 
Tampering is not legal. EPA enforces these prohibitions to protect public health and the environment. Emissions controls prevent respiratory disease, premature death, and environmental harm. “Rolling coal” is specifically banned in Maryland and actually decreases fuel economy and engine efficiency. 

Does this apply to me?

 

These prohibitions apply to anyone who services any emissions-related aspect of any EPA-certified vehicle, engine, or piece of equipment. They also apply to anyone who manufactures, distributes, or installs emissions-related parts.

What is the penalty for vehicle tampering?

 
The Code of Maryland Regulations 26.11.20.02 prohibits tampering.  Violation of Maryland’s anti-tampering laws may result in a civil penalty of up to $25,000 per day per violation (Environment Article, Annotated Code of Maryland, §§ 2-610 and 2-610.1).  In addition, a person who knowingly tampers with a vehicle may be found guilty of a misdemeanor, and subject to a fine not exceeding $25,000, imprisonment of up to 1 year, or both for a first offense (Environment Article, Annotated Code of Maryland, § 2-609.1). 
  
Under federal law, anyone who sells or installs a device to defeat emission controls can be fined up to $4,800 for each defeat device, and dealers can be fined up to $48,000 for every tampered vehicle (these values periodically increase pursuant to 40 CFR § 19.4) . In the past few years EPA has closed over 60 civil tampering cases, and the Department of Justice has filed criminal charges in others.

Will tampering affect my vehicle's warranty?

 

Under the Clean Air Act, car manufacturers are required to provide a warranty covering emission control devices for five years or 50,000 miles, whichever comes first. However, when a car's emission controls have been tampered with, the manufacturer will not honor the vehicle's warranty.

Why do people tamper with vehicle emissions systems?

 

Some people believe that removing emissions equipment can improve vehicle performance or reduce the costs of maintenance. The reality is tampering with emissions equipment will often cause drivability issues, decrease performance, result in increased longer-term maintenance costs, and shorten the life of the engine.

Others tamper with emissions equipment in order to “roll coal” by emitting visible black smoke.

Deleting emissions equipment on one truck could cause it to emit as much harmful pollution as 300 untampered trucks and can void the vehicle warranty. Such tampering makes sale of the vehicle illegal, and the costs to replace the removed emissions equipment can be thousands of dollars 

How can I avoid tampering?

 

Emissions controls are all parts that may affect emissions, such as catalysts, filters, the electronic control unit, the fuel system, and the on board diagnostic system. 

  • Do not remove or change emission controls on any EPA-certified vehicle, engine, or piece of equipment 
  • Do not sell, lease, or offer for sale or lease any vehicle with a tampered emissions system 
  • Do not purchase a tampered vehicle from any person, dealer, or auto auction 
  • Do not install any non-compliant emission control devices on your vehicle or engine. Use only EPA or California Air Resources Board (CARB) approved replacement parts

What should I look for when buying a used vehicle?

 

Before buying ask the seller if the vehicle meets all federal and state emission system tampering laws. 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 vehicle have them 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 looked over. It is a good practice to take a used vehicle you are considering buying to a repair technician you trust. 

 

 Dealer FAQs

 

May I sell a vehicle that has been tampered?

 

​Federal law prohibits offering for sale or transferring ownership of a motor vehicle unless all air pollution control systems are in place and in operating condition. Even vehicles sold “as is” or without warranty must comply with anti-tampering laws. Tampering with, or selling a vehicle that has been tampered with, may result in monetary penalties. The components of a vehicle emission control system that can be tampered with include, but are not limited to: 

  • catalytic converter 
  • air injection system
  • evaporative emission system
  • exhaust gas recirculation (EGR) 
  • system fuel inlet restrictor 
  • oxygen sensor
  • positive crankcase ventilation (PCV) 
  • computer command controls
  • thermostatic air intake​ system
  • diesel particulate filter

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

 

No. The trade-in transaction is considered a sale, and this act would violate the anti-tampering law. 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, and work out the repair costs as part of the trade-in agreement.

Am I protected from fradulent consumer claims of tampering?

 

To protect yourself from the consequences 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.

Manuals are available for purchase 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.

 

 Repair Industry FAQs

 

What is tampering when repairing a vehicle?

 
If you remove, disconnect, detach, deactivate, alter, modify, reprogram, or make less effective any emission control device installed by the manufacturer, or use less effective replacement parts, you have committed the act of tampering. This includes installing replacement parts that don’t meet the manufacturers’ specifications, reprogramming computer components or installing performance chips to bypass or defeat factory settings. The components of a vehicle emission control system that can be tampered with include, but are not limited to: 
  • catalytic converter 
  • air injection system 
  • evaporative emission system 
  • exhaust gas recirculation (EGR) 
  • system fuel inlet restrictor 
  • oxygen sensor
  • positive crankcase ventilation (PCV) 
  • computer command controls 
  • thermostatic air intake system 
  • diesel particulate filter​

May I work on a vehicle that has previously been tampered with?

 

Yes. However, if you are replacing a part that is not the proper part for that vehicle and emission system, then you are required to put the proper parts back on the vehicle. If you perform any work on any part of the vehicle which has been previously tampered with, you must perform the correct repair or not do it at all in order to not be liable for tampering. This is true regardless of the age or mileage on the vehicle, and applies to any motor vehicle which was designed to meet federal emissions standards

Do repair technicians have to use Original Equipment Manufacturer (OEM) parts?

 

​No. You may also use rebuilt parts or equipment made by independent aftermarket parts manufacturers. Replacement parts must be equivalent in design and function to the parts that were originally on the vehicle when it was certified and must not have a negative effect on emission control. To be certain you're using acceptable replacement parts, get a written statement from the parts manufacturer saying that the replacement part conforms in design and function with the original part.​

Is it illegal to replace a catalytic converter with a section of pipe?

 

​Yes. If a repair facility completes, assists, or participates in any way of tampering begun by someone else, it has also violated state and federal tampering laws.​

What can I do to remain in compliance?

 

  • Before accepting a vehicle as a trade-in, make sure it meets all federal and state emission system tampering laws
  • Before offering a vehicle for sale, ensure that the emissions control system is fully functional and has not been tampered with
  • If you service vehicles, perform all work on emission controls according to manufacturer specifications and do not tamper with vehicle emission controls
  • Do not advise customers on how to tamper with their vehicle emission controls 
  • Do not work on tampered emission controls unless restoring them to their original condition or you can be held personally liable