General Motors alleged diesel emission cheating scandal

General Motors

General Motors to face allegations of diesel emission cheating

General Motors is the latest vehicle manufacturer to face allegations of emission cheating.  After the Volkswagen TDI emission case scandal, there was numerous allegations, lawsuits and investigations with the new diesel models from nearly every vehicle manufacturer. General Motors is the latest one. The allegations is against its popular LML 6.6 Duramax diesel V-8 engine, offered in 2011-2016 Chevrolet Silverado and GMC Sierra HD pickups.

The lawsuit was filed on May 24 by the Hagens Berman Sobol Shapiro firm. It is the same firm involved in the Volkswagen emissions case and the Fiat Chrysler Automobiles (FCA) EcoDiesel case. According to reports, the lawsuit claims that GM pickup trucks with Duramax diesel engines include three devices that are rigged to allow more pollution on the road than during tests in the Environmental Protection Agency laboratory.


The firm alleges that the exhaust system design of the General Motors trucks was designed to work around regulations by placing the selective catalyst reduction system ahead of the diesel particulate filter.

This optimizes power output while making the truck perform favorably under lab conditions for cold start emissions. But it is alleged that this design increases real-world NOx emissions and increase fuel-consumption and decreasing power.

Bosch, the supplier of the fuel system for the LML Duramax is included in the lawsuit as well, as there are claims that the supplier had a full knowledge of the software scheme and the operating parameters of the engine controls.

The lawsuit was filed on behalf of owners and lessees of more than 705,000 Silverado and Sierra trucks equipped with Duramax engines.

General Motors denies all allegations and say that they will defend themselves against all accusations.


“These claims are baseless and we will vigorously defend ourselves,” according to a May 25 GM statement.

“The Duramax diesel Chevrolet Silverado and GMC Sierra comply with all U.S. EPA and CARB emissions regulations.”

Diesel engines have been under scrutiny since Volkswagen made national headlines for a diesel emissions cheating scandal that has resulted in a nearly $15-billion settlement with the U.S. government.