GM Accused of Cheating on Emissions Tests for Big Diesel Engines

Promo image. GM with Duramax engine

Everybody loves pickup trucks in America, the bigger the better. And the biggest and baddest GM pickups are often powered by giant Duramax diesel engines. These engines are marketed as being clean diesels, but a recent lawsuit claims that GM has been using defeat devices (like Volkswagen did) to fudge the emissions tests. The first two paragraphs are fun:

1. This is what General Motors (“GM”) promised when selling its popular Silverado and Sierra HD Vehicles—that its Duramax engines turned “heavy diesel fuel into a fine mist,” delivering “low emissions” that were a “whopping reduction” compared to the prior model and at the same time produced a vehicle with “great power.” GM claimed its engineers had accomplished a “remarkable reduction of diesel emissions.”
2. As explained in detail below, this is not what GM delivered in the estimated 705,000 or more Silverado and Sierra diesels on the road. In contrast to GM’s promises, emissions testing has revealed that the Sierra and Silverado models emit levels of NOx many times higher than (i) their gasoline counterparts, (ii) what a reasonable consumer would expect, (iii) the Environmental Protection Agency’s maximum standards, and (iv) the levels set for the vehicles to obtain a certificate of compliance that allows them to be sold in the United States.
The class action suit, filed on behalf of 705,000 people who own or lease the monster trucks, makes interesting reading, going on for 191 pages. It also explains the attraction of diesels in big trucks and pickups:
Diesel engines pose a difficult challenge to the environment because they have an inherent trade-off between power, fuel efficiency, and emissions. Compared to gasoline engines, diesel engines generally produce greater torque, low-end power, better drivability, and much higher fuel efficiency. But these benefits come at the cost of much dirtier and more harmful emissions.

But as pickups have moved from being commercial and farm vehicles to being family cars, those emissions have become a serious problem. The lawyer handling the suit put out a press release where they note how much bigger these engines are that the little diesels in VW passenger cars.

“This is a shocking discovery, and a really big deal because the NOx limits for these big trucks are four times what the limits were for the much smaller Volkswagen passenger cars and there are more of these trucks on the road,” explained [managing partner] Berman. “As a result, these GM trucks likely dumped as much excess poisonous NOx emissions into our air as did the cheating Volkswagen passenger cars.”
Duramax Diesel

© General Motors Duramax Diesel

GM and Bosch, which supplied diesel controls and has lots of European experience with defeat devices (and paid $327.5m to the US government to settle its part in the VW emissions scandal) deny that there is a problem and tell CNBC:

A GM spokesman told CNBC that the "claims are baseless and we will vigorously defend ourselves. The Duramax diesel complies with all U.S. EPA CARB emissions standards." A Bosch representative told CNBC the company "takes the allegations of manipulation of diesel software very seriously. Bosch is cooperating with the continuing investigations in various jurisdictions, and is defending its interests in the litigation."
statistics on deaths

© New Scientist

We do go on about how these big pickups are such a danger to pedestrians and cyclists, with their giant flat front ends. Now we find that they are poisoning us too. Enough already.

Here is the entire surprisingly readable legal document of the Gm Lawsuit by Ryan Felton on Scribd.