United States Environmental Protection Agency	EPA 300-F-20001
Office of Enforcement and Compliance Assurance	December 2020

j Enforcement Alert
% PROt^
Aftermarket Defeat Devices and Tampering are Illegal and Undermine
Vehicle Emissions Controls
Purpose
This Alert is intended to remind all regulated entities that installing a defeat device or tampering with a motor
vehicle or non-road equipment can be costly to their businesses and can subject them to enforcement and
penalties. The U.S. Environmental Protection Agency (EPA) remains concerned that regulated entities are
continuing to ignore the prohibitions against tampering in section 203(a)(3) the Clean Air Act and 40 C.F.R.
§§ 1068.101(b), despite the EPA resolving over seventy cases in the last five years. EPA has identified Stopping
Aftermarket Defeat Devices for Vehicles and Engines as a National Compliance Initiative
(https://www.epa.gov/enforcement/national-compliance-initiatives). While EPA continues to take enforcement
actions against automobile manufacturers for their emissions cheating, the focus of this National Compliance
Initiative is on those who manufacture, sell, or install aftermarket parts known as defeat devices, which bypass
or render inoperative required emissions control systems, resulting in significant increases in harmful air
emissions.
The Clean Air Act requires vehicle and engine manufacturers to demonstrate that their products do not exceed
applicable emission limits. The Clean Air Act also prohibits anyone from manufacturing, offering for sale, selling,
or installing any part or component that bypasses or defeats emissions controls.
These requirements mean that emissions-related parts and
elements of design must not be changed, including any part,
device or element of design installed on or in a motor vehicle,
non-road equipment, motor vehicle engine, or non-road engine
by an Original Equipment Manufacturer (OEM) for the specific
purpose of controlling emissions. Examples of such parts,
devices, and elements of design include: the on-board
diagnostic system (OBD); diagnostic trouble codes (DTCs);
sensors for oxygen, oxides of nitrogen (NOx), ammonia,
particulate matter (PM), urea quality, and exhaust gas
temperature; diesel particulate filters (DPFs) and their sensors;
exhaust gas recirculation (EGR) systems; diesel oxidation catalysts (DOCs); selective catalytic reduction (SCR)
systems; NOx adsorber catalyst (NAC) systems; engine calibrations that affect engine combustion (e.g., fuel
injection or ignition timing, injection pattern, fuel injection mass for each injection event, fuel injection pressure,
EGR flowrate, mass air flowrate, EGR cooler bypassing); and any other part, device, or element of design
installed on certified vehicles or engines in compliance with Title II of the Clean Air Act and its regulations,
including parts and specifications included in the manufacturer's tested prototype.

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LAW PROHIBITS TAMPERING AND THE MANUFACTURE, SALE, AND
INSTALLATION OF DEFEAT DEVICES
Section 203(a)(3)(B) of the Clean Air Act makes it a violation for any person to manufacture or sell, or offer to
sell, or install, any part or component (i.e., "defeat device") intended for use with, or as part of, any motor
vehicle or motor vehicle engine, where a principal effect of the part or component is to bypass, defeat, or render
inoperative any device or element of design installed on or in a motor vehicle or motor vehicle engine in
compliance with regulations under Title II of the Clean Air Act, and where the person knows or should know that
such part or component is being offered for sale or installed for such use or put to such use.
Also, section 203(a)(3)(A) of the Clean Air Act
prohibits any person from knowingly removing or
rendering inoperative (i.e., "tampering") any such
emissions control device or element of design.
EPA regulations establish the same prohibitions on
tampering and defeat devices for nonroad vehicles,
engines, and equipment. 40 C.F.R. §§ 1068.101(b).
Many states also have prohibitions on tampering
and aftermarket defeat devices. These laws vary, but
in some cases include prohibitions on the operation
of a tampered vehicle or engine, and prohibitions on
the sale or registration of tampered vehicles.
WHAT DOES IT MEAN TO HAVE A REASONABLE BASIS?
The EPA focuses its enforcement activities on the sale and use of
aftermarket parts that increase emissions. The EPA generally
takes no enforcement for manufacturing, sale, or installation of
aftermarket parts against any person who has a reasonable basis
for knowing that use of such part will not adversely affect
emissions performance. EPA's decades-long practice when
enforcing the prohibitions on tampering and aftermarket defeat
devices has been to accept that there is a reasonable basis to
show there is no adverse effect on emissions in each of the
following circumstances:
1.	The aftermarket part is identical in design and function to the part or component it replaced.
2.	The vehicle or engine, as modified, meets emissions standards when tested on the same tests as the
OEM used to certify the vehicle with the EPA.
3.	The California Air Resources Board (CARB) has issued an Executive Order (EO) that covers the same
device or part on the same model vehicle on which the device or part was installed.


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This means that aftermarket part manufacturers,
sellers, and installers can avoid enforcement
action by having proof before manufacturing,
selling, and installing parts or components that
they will not increase emissions. As noted above,
emissions test results using the same tests used to
certify the applicable vehicle or engine can be
used to demonstrate compliance, or an Executive
Order from CARB demonstrating no increase in
emissions for the intended use of the part.
VIOLATING THE LAW IS COSTLY
Violation of the tampering and defeat device
prohibitions of the Clean Air Act may result in civil
penalties. As of January 13, 2020, a person may
be liable for a maximum civil penalty of $4,819
per defeat device manufactured, sold, or installed,
or per vehicle tampered. A dealer or vehicle
manufacturer who tampers with a vehicle may be
subject to significantly higher civil penalties. Clean
Air Act section 205(a); 40 C.F.R. §19.4. This per
defeat device penalty can add up to a very large
penalty when many such products have been
sold, as, for example, in a recent case against
Performance Diesel, Inc. (see text box).
Tampering, including installation of a defeat
device, can void manufacturer warranties. Also,
tampered vehicles and engines may not be
covered by insurance policies, and states may
prohibit the registration of tampered vehicles and
engines.
PERFORMANCE DIESEL, INC. STOPS SELLING DIESEL
ENGINE DEFEAT DEVICES AND PAYS PENALTY
In 2019, Performance Diesel, Inc. (PDI) agreed to resolve
alleged violations of the Clean Air Act associated with the
sale of at least 5,549 aftermarket products that defeat the
emissions control systems of heavy-duty diesel engines in
violation of the Clean Air Act.
PDI manufactured, sold, and installed electronic tuning
software, known as "tunes," that reprogramed a motor
vehicle's electronic control module to alter engine
performance and enable the removal of filters, catalysts,
and other critical emissions controls. PDI's aftermarket
products were designed for use with numerous models of
certified heavy-duty diesel engines.
Under the terms of this settlement, PDI must:
•	stop the manufacture and sale of all products that
violate the Clean Air Act;
•	demonstrate that their products do not increase
emissions by performing emissions testing that
satisfies CARB's requirements for obtaining an EO
prior to manufacture, sale, offering for sale, and
installation of products; and
•	pay a civil penalty of $1,100,000 (based on PDI's
demonstrated inability to pay the higher penalty
warranted by the alleged violations).
For more information on the case, please visit:
https://www.epa.gov/enforcement/performance-diesel-
inc-clean-air-act-settlement-information-sheet.
DEFEAT DEVICES HARM AIR QUALITY AND PUBLIC HEALTH
EPA testing demonstrates that vehicles equipped with defeat devices can produce significantly more air
pollution than compliant vehicles. Removing emissions controls from vehicles presents a threat to public health.
Increased emissions including particulate matter, hydrocarbons, and oxides of nitrogen have been linked to:
•	Premature death in people with heart or lung disease
•	Nonfatal heart attacks
•	Irregular heartbeat
•	Aggravated asthma
•	Decreased lung function
•	Increased respiratory symptoms, such as irritation of the airways, coughing or difficulty breathing

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CLAIMS OF COMPETITION-USE ONLY
The EPA has found that many companies that make and sell aftermarket defeat devices claim "competition
only" use but cannot provide any information to show that their products are used solely in competition
motorsports. The Clean Air Act does not contemplate removing emissions controls from an EPA-certified motor
vehicle in order to convert it into a competition vehicle. As a matter of enforcement discretion, the EPA's
longstanding practice has been not to take enforcement action against vehicle owners for removing or defeating
the emission controls of their EPA-certified motor vehicles, so long as they can show the vehicles are used solely
for competition events and no longer driven on public roads.
Recent EPA investigations have revealed evidence showing that hundreds of thousands of diesel pickup trucks
have had their emissions controls completely removed, and most or all the aftermarket defeat devices used to
tamper these trucks were sold under the claim of "competition only." The sheer volume of aftermarket defeat
devices belies the assertion that they are only for competition motorsports.
PUNCH IT PERFORMANCE AND TUNING AGREES TO STOP SELLING ILLEGAL DEVICES THAT DEFEAT
EMISSIONS CONTROL SYSTEMS AND PAYS PENALTY
In 2020, the United States reached a settlement with Punch It Performance and Tuning, Michael Paul
Schimmack, and affiliated companies and individuals. This settlement resolved the United States' allegations
that the defendants manufactured and sold products for pickup trucks that altered engine performance and
enable the removal of filters, catalysts, and other critical emissions controls. In addition, certain defendants
allegedly transferred assets in an effort to avoid payment of penalties in the case.
Under the settlement, the defendants must stop the manufacture and sale of all products that violate the
Clean Air Act. They must also surrender the computer code and other intellectual property used in the illegal
products, and they must stop providing technical and warranty support for the defeat devices already sold.
Finally, the defendants must pay a civil penalty of $850,000. After the EPA notified the defendants in 2016 of
its intent to take enforcement action, the corporate defendants transferred real estate and monetary assets
to one or more of the individual defendants in their personal capacities. The United States alleged these
were fraudulent transfers under the Federal Debt Collection Procedures Act. Accordingly, the individual
defendants paid some of the civil penalty by selling personal assets.
For more information on the case, please visit: https://www.epa.gov/enforcement/punch-it-performance-
clean-air-act-settlement
CRIMINAL PROHIBITIONS
It is a crime to knowingly falsify, tamper with, render inaccurate, or fail to install any "monitoring device or
method" required under the Clean Air Act, including a vehicle's on-board diagnostic system. Clean Air Act
section 113(c)(2)(C). The EPA has criminally prosecuted such conduct (see text box below).

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REPORT PROBLEMS
If you suspect someone is manufacturing,
selling, or installing illegal defeat devices or is
tampering with emissions controls, tell the EPA
by emailing: tampering@epa.gov
BENEFITS OF THE EPA'S SELF-
DISCLOSURE POLICIES
Regulated entities of any size who voluntarily
discover, promptly disclose, expeditiously
correct, and take steps to prevent recurrence
of potential violations may be eligible for a
reduction or elimination of any civil penalties
that otherwise might apply. Most violations
can be disclosed and processed via the EPA's
automated online "eDisclosure" system (see
https://www.epa.gov/compliance/epas-
edisclosure). To learn more about the EPA's
violation disclosure policies, including
conditions for eligibility, please review the
EPA's Audit Policy at
https://www.epa.gov/compliance/epas-audit-
policv. Many states also offer incentives for
self-policing. Please check with the
appropriate state agency for more
information.
SIX CHARGED WITH CONSPIRING TO DEFRAUD THE
UNITED STATES AND VIOLATE THE CLEAN AIR ACT
Six individuals with various relationships to Rockwater
Northeast LLC (Rockwater), a hauling service for the oil and
gas industry in Pennsylvania, were charged with conspiring
to violate the Clean Air Act. The men conspired to modify
the emissions systems on approximately thirty Rockwater
heavy-duty diesel trucks by using aftermarket defeat
devices. The purchase of the defeat devices was concealed
in Rockwater's books and records by mislabeling them as
exhaust systems. The conspirators were also accused of
taking the modified commercial motor vehicles to state
approved inspection stations to pass federally regulated
commercial motor vehicle inspections falsely.
Sentencing proceedings for the defendants began in
February of 2020 and, as of this writing, one defendant has
been sentenced to six months imprisonment. Rockwater
agreed to pay a $2 million dollar penalty and Select Energy
Solutions, Inc., a Texas-based successor in interest to
Rockwater, agreed to pay a $2.3 million dollar penalty.
For more information on the case, please visit:
https://www.iustice.gov/usao-mdpa/pr/water-
management-companies-enter-resolutions-pay-43-
mimillion-monetarv-penalties-clean
FOR MORE INFORMATION
Mobile source air enforcement policy and publications can be found at
https://www.epa.gOv/enforcement/air-enforcement-policv-guidance-and-publications#Mobile. This
includes a 2020 policy called "EPA Tampering Policy: The EPA Enforcement Policy on Vehicle and Engine
Tampering and Aftermarket Defeat Devices under the Clean Air Act," which describes what constitutes a
"reasonable basis" for knowing that a part or component does not adversely affect emissions.
DISCLAIMER
This Enforcement Alert addresses select provisions of EPA legal requirements using plain language. Nothing in
this Enforcement Alert is meant to replace or revise any EPA regulatory provisions, policies, parts of the Code of
Federal Regulations, the Federal Register, or the Clean Air Act.

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