Man pleads guilty in truck emission-defeating scheme

November 29, 2023

Tyson Fisher


A former trucking company employee pleaded guilty for his role in a scheme that tampered with the emission controls of hundreds of trucks in violation of the Clean Air Act.

James Sisson pleaded guilty in a U.S. District Court for the Western District of Michigan to conspiracy to violate the Clean Air Act. Sisson, two trucking companies and several employees installed defeating devices that bypassed emission controls in hundreds of trucks.

‘Masters’ and ‘slaves’

The emission-defeating devices were employed by two Michigan trucking companies using a system with components referred to as masters and slaves.

According to the indictment, a company in Italy referred to as Company 1 developed software used in connection with the deletion of emissions control components and distributed that software to other members of the conspiring group. It was distributed in North America by an Ohio company referred to as Company 2.

Companies 1 and 2 designated their downstream customers, who further distributed and implemented the deletions, as masters and slaves. Masters were programmers that used the software to reprogram the engine computer for a truck at the shop of a slave. The slaves completed the hardware component of the deletion and connected the engine computer to the internet by using so-called “slave tools” that facilitated this connection.

Masters were encouraged by Companies 1 and 2 to recruit slaves. Companies 1 and 2 provided training and support to their downstream customers to help them successfully implement deletions on vehicles with heavy-duty diesel engines.

Trucking companies used emissions-defeating devices

The indictment names Michigan trucking companies and its employees in a scheme to use the emissions-defeating devices.

Diesel Freak of Gaylord, Mich., was a master with dozens of slaves in the United States, according to court documents. One of the slave companies was Grand Rapids, Mich.-based Accurate Truck Service.

From February 2015 to November 2018, Diesel Freak deleted, or aided and abetted the deletion of, at least 362 vehicles.

Accurate Truck Service conducted deletions by removing the hardware components of vehicles with heavy-duty diesel engines. Diesel Freak provided remote reprogramming services for those deletions. Diesel Freak and Accurate Truck Service used code words like “ECM wiring” on invoices to conceal the fact that the work performed was a deletion.

Several individuals sentenced

Sisson is just the latest individual in the emissions scheme to plead guilty. Several more have already been sentenced.

According to court records, seven individuals involved in the scheme have already pleaded guilty and been sentenced:

  • Glenn Hoezee, sentenced to 12 months of probation, $4,000 fine
  • Robert Swainston, sentenced to 12 months of probation, $4,000 fine
  • Randy “Jeb” Clelland, sentenced to 12 months of probation, $4,000 fine
  • Ryan Bos, sentenced to 12 months of probation, $6,000 fine
  • Scott DeKock, sentenced to 12 months of probation, $10,000 fine
  • Craig Scholten, sentenced to 12 months of probation, $6,000 fine
  • Douglas Larsen, sentenced to 12 months of probation, $7,500 fine

Accurate Truck Service also has been sentenced to 12 months of probation and issued a $500,000 fine. A hearing for Diesel Freak is scheduled for Jan. 26, 2024.

“By illegally tampering with emissions controls on diesel trucks operating throughout the United States and Canada, defendants caused the excessive release of diesel exhaust containing toxic gases and impurities harmful to public health and the environment,” Acting Special Agent in Charge Richard Conrad of the U.S. Environmental Protection Agency’s Criminal Investigation Division said in a statement. “This case highlights EPA and our law enforcement partners’ continued efforts to prosecute those who violate environmental and public health laws in the U.S. for financial gain.” LL

Find more trucking news at