A week after General Motors was hit with a potential class action lawsuit related to the carmakers admission that it had incorrectly calculated the fuel economy on several SUV models, the company’s Chevrolet division is facing a second lawsuit alleging it tricked consumers into paying more for diesel-engine Chevy Cruze Turbo sedans equipped with emissions-cheating software.  

Owners of Chevy Cruze Turbo Diesel vehicles filed the lawsuit [PDF] in a U.S. District Court in California this week accusing the company of deceptively marketing the vehicles as “GM’s cleanest diesel engine ever” even though they knew the cars produce illegally high levels of pollution.

According to the lawsuit, the Cruze Turbo Diesel is advertised as a “clean diesel” with emissions below U.S. Environmental Protection Agency standards and sold for an additional $2,000 or more compared to similar gasoline models.

The lawsuit claims that GM’s recall of Cruze and Opel Zafira vehicles in Germany after an environmental group issued a report indicating excessive nitrogen oxygen emissions is evidence that the U.S.-based vehicles include the same issues.

Like Volkswagen vehicles that were found to contain emissions-cheating “defeat devices,” the lawsuit claims that the software inside the Cruze allows it to turn on emission controls during laboratory testing, but turn off the controls — and emit more pollutants — during real world driving.

The suit claims the diesel-engine Cruze emits far more pollution on the road than in lab tests and that these vehicles exceed federal and state standards for nitrogen oxide emission by 1.8 to 13.8 times.

In fact, the tests found that in highway driving the Cruze averaged 128 mg/mile with a high of 557 mg/mile, while stop-and-go driving averaged 231 mg/mile, translating to about 1.8 to eight times the federal standards.

“Testing also reveals that GM intentionally defeats emissions controls,” the suit states. “The drastic change in emission controls at high and low speeds is indicative of the use of a defeat device. This contrast demonstrates that GM has programmed its emission systems to reduce effectiveness or turn off altogether when the vehicle is on the road.”

With the lawsuit, Cruze owners are seeking an order for GM to buyback their vehicles, reimburse them for the premium they paid, and compensation based on any remedy put in the place in the future.

A spokesperson for GM tells Consumerist, “These claims are baseless, and we will vigorously defend ourselves.  GM believes the Chevrolet Cruze turbo diesel complies with all U.S. EPA and CARB emissions regulations.”

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