Truck repair shops admit to conspiracy to tamper with emissions control systems

Two diesel repair companies have pleaded guilty to conspiring to violate the Clean Air Act, according to the U.S. Attorney’s Office for the District of Colorado.

Authorities say that Pro Diesel Inc. and Endrizzi Diesel, LLC. admitted to conspiring with a Colorado-based diesel shop to remove or alter the monitoring component of emissions control systems on Class 8, commercial heavy-duty diesel trucks and semi trucks, thereby violating the Clean Air Act.

Authorities say that between July 2017 and May 2020, Iowa-based Pro Diesel Inc. paid a Colorado diesel shop identified as “E.D.” more than $76,000 to disable on-board diagnostic systems on 34 Class 8 trucks. And, between January 2017 and December 2020, Missouri-based Endrizzi Diesel, LLC paid E.D. more than $149,000 to disable the diagnostic systems on approximately 60 class 8 trucks.

From the U.S. Attorney’s Office:

On-board diagnostics systems (OBDs) are monitoring devices required under the Clean Air Act to be installed on vehicles to monitor emissions control systems and to ensure they are functioning properly. Tampering an OBD is frequently referred to as “tuning.” One purpose for “tuning” an OBD is to allow the vehicles to continue to seemingly operate normally while the emissions control system is disabled. This reduces the high costs associated with maintaining or repairing components of the emissions control systems on heavy-duty diesel trucks.  However, as a consequence, tampered vehicles spew substantially more deleterious pollutants such as nitrogen oxides, carbon monoxide, non-methane hydrocarbons and particulate matter into the air, presenting a risk to the environment and public health. Nitrogen oxides from tailpipe emissions are a major contributor to the creation of ozone on the front range. Tests conducted by the EPA have found that completely deleting a diesel pickup truck’s emissions controls can increase the truck’s tailpipe emissions of nitrogen oxide by a factor of approximately 310 times, carbon monoxide by a factor of approximately 120 times, and non-methane hydrocarbons by a factor of approximately 1,100 times. The pollutant increase is even greater when the emission controls on Class 8 vehicles, such as the ones tampered with here, are disabled.

Through a remote connection, individuals at E.D. would run software programs to reprogram or “tune” the vehicle’s on-board diagnostic systems. These programs would tamper with, render inaccurate, and disable the monitoring functions of the OBDs so they would no longer detect malfunctions in the emissions control systems.

Sentencing is scheduled for Pro Diesel June 14, 2022.

Endrizzi Diesel will be sentenced on June 29, 2022.