A proposed class action alleges scores of trucks and SUVs made and sold by General Motors after 2009 suffer from a defect that can prevent the seatbelts from tightening and the airbags from deploying in certain types of crashes.
The sprawling 164-page lawsuit says the alleged defect stems from the sensing and diagnostic module (SDM) within each affected vehicle’s airbag control unit. The SDM, a small computer connected to sensors throughout the vehicle, is responsible for detecting irregular behavior and firing the airbags and tightening the seatbelts during a crash, the suit relays.
According to the complaint, however, the software that controls an affected vehicle’s SDM was calibrated by GM to prevent airbag and seatbelt deployment just 45 milliseconds after a crash has begun. This means a truck or SUV’s airbag may not deploy and seatbelts may not tighten in real-world accidents that last longer than 45 milliseconds—such as those that involve multiple impacts or increase in severity, according to the lawsuit, which was filed by eight plaintiffs in Michigan on August 5.
An example of a crash in which a GM truck or SUV’s airbag and/or seatbelts might not deploy, the suit explains, is one during which a vehicle first hits a curb or speed bump before crashing into a tree or other vehicle. In such an event, the vehicle’s SDM will fail to trigger the airbag and/or tighten seatbelts should the time after the first impact with the curb or speed bump last longer than 45 milliseconds prior to the subsequent, more serious impact, according to the complaint.
Per the case, a team of software engineers at Delco Electronics, who designed the SDM software program in all affected GM vehicles, expressly warned “Old GM”—that is, the General Motors that existed prior to its June 2009 bankruptcy filing—more than 20 years ago that preventing airbag and seatbelt deployment after 45 milliseconds was a “reckless and dangerous decision.” The lawsuit alleges Old GM’s trucks division “ignored this warning” and insisted on using a defective SDM calibration that shuts off the airbags after 45 milliseconds—even though a separate team in charge of Old GM’s cars tellingly rejected the 45-millisecond approach after hearing Delco’s concerns and instead implemented a 150-millisecond deployment window for airbags and seatbelts during a crash, the filing adds.
Although the reckless decision to use dangerous SDM calibration was known to General Motors upon its formation in 2009, the automaker, according to the lawsuit, “continued to use Delco SDMs in its vehicles and … continued to use the defective calibration associated with those Delco SDMs as well.” The case alleges GM has concealed its knowledge of the SDM calibration defect and failed to recall or repair affected vehicles “presumably to avoid the significant costs and inconveniences” of pulling millions of trucks and SUVs off the market.
“GM has hidden the defect in spite of its obligation to disclose it, misrepresented the Class Vehicles to be safe, and continued to sell them to consumers,” the complaint alleges, asserting that drivers nationwide are “unaware that their airbags and seatbelts may not operate in a prolonged frontal crash.”
Publicly available consumer complaints to the National Highway Traffic Safety Administration detail more than 800 instances in which airbags and/or seatbelts “suspiciously” failed in affected GM vehicles during frontal crashes, the lawsuit continues. Per the case, many of these reports allege GM “knew about and investigated the crash after the reported airbag failures.” A separate NHTSA dataset indicates that nearly 1,300 people from 1999 through the present were killed or injured in a frontal collision in which the airbags of their GM vehicle did not deploy, the complaint says.
How sensing and diagnostic modules should work
A truck or SUV’s sensing and diagnostic unit is effectively the brain behind a vehicle’s safety systems. It operates in three basic phases, with the first being a resting or “normal” mode. In this mode, the case says, the SDM receives signals from sensors throughout the vehicle that collect and report information on, for example, acceleration, wheel speed, brake pressure and impacts. The SDM monitors and interprets these signals to determine whether a vehicle is involved or is about to be involved in an accident, the lawsuit says.
If and when an SDM detects an irregular input, suggesting a potential accident, it essentially “wakes up” into its second mode to search for confirmation of a crash, as opposed to, for instance, an irregular input from slamming on the brakes and then avoiding a collision, according to the suit. In this second mode, the complaint goes on, the SDM’s crash-sensing software algorithm is tasked with quickly figuring out crash status and should issue a command to fire the airbag and/or tighten the seatbelts as needed in the event additional inputs confirm that a crash has taken place.
An SDM’s third and final phase is its “reset” phase, wherein the unit ultimately resets after it detects that a crash or a potential crash has fully completed, the case explains. Overall, all three phases of an SDM’s operation might take only fractions of a second, the filing says.
“Indeed, a typical ‘crash duration’ in a frontal, vehicle-to-barrier collision lasts for approximately 80-150 milliseconds (0.08-0.15 seconds),” according to the lawsuit. “For that reason, timing this sequence properly is critically important to ensure that the seatbelts are tightened and the airbags deploy to protect occupants when they need to.”
Crucially, the software that controls a GM vehicle’s SDM must be calibrated properly to recognize and react to crashes in real time so the airbags inflate when they are needed, the complaint stresses. In the affected GM trucks and SUVs, called the “class vehicles,” this critical software is faulty, the lawsuit alleges:
Specifically, for frontal crashes, GM calibrated the SDM to prevent deployment of airbags and pretensioners more than 45 milliseconds after it enters ‘wake up’ mode. GM did this by increasing the deployment thresholds to unattainable values 45 milliseconds into the crash sequence. With this calibration in place, no matter how severe the inputs the SDM received after 45 milliseconds, the airbags and pretensions would not deploy.”
Put simply, frontal crashes, specifically “concatenated” events with multiple distinct points of impact, that go on for 45 milliseconds or longer and require airbag deployment or seatbelt tightening may not have use of these safety features, according to the case:
A vehicle that first hits a curb and then veers and hits a tree, or first hits a speed bump and then crashes into the vehicle in front of it, are examples of concatenated crashes. By their nature, concatenated accidents involve multiple discrete inputs for the SDM to detect during a crash sequence.”
The suit charges that the 45-millisecond gap in protection is unreasonably dangerous given real-world accidents are “not necessarily completed at that point.” In many instances, a crash continues, and seatbelts and airbags are needed, well after that time, yet GM’s SDM software calibration makes it impossible for the critical safety features to do their jobs in the “dead zone” that occurs just 45 milliseconds after the initial impact, the complaint says.
What GM allegedly knew—and when
General Motors “knew or had reason to know” of the SDM calibration defect and its associated safety risks as far back as July 10, 2009, when it acquired substantially “all of Old GM’s books, records, and personnel” and the details of the SDM software calibration, the case contends. Nevertheless, the automaker has “continued to conceal this problem and the pattern of accidents, injuries, and deaths that have resulted from it” by, for instance, failing to share its information with consumers who’ve bought or leased GM-made trucks and SUVs, the suit claims.
The complaint goes on to scathe that it “should come as no surprise that GM has unreasonably and unsafely delayed disclosure” of the SDM issue. As the lawsuit tells it, GM attempted to “avoid the costs, potential liabilities, and reputational harms” of the Takata airbag safety recall and “seems to have repeated the same tactic here” with regard to the SDM calibration defect. From the complaint:
As is now public knowledge, millions of GM vehicles contain the dangerous and defective Takata airbag inflators that can explode with too much force and spray metal shrapnel into vehicle passenger compartments. While the dangers of these Takata airbags were widely known for years, GM lobbied regulators to delay a recall for its affected vehicles to avoid a resulting hit to its profits. In 2016, GM reported that recalling its vehicles with Takata inflators would cost hundreds of millions of dollars.
Here, as in Takata, GM knew or should have known that the SDM software calibration in the Class Vehicles—which includes a dead zone that prevents the airbag and seatbelts from deploying after 45 milliseconds—was dangerous. Nonetheless, GM kept using it anyway, did not recall or repair the Class Vehicles to correct it, and still has not told consumers about it.”
General Motors is alleged in the proposed class action to have violated federal consumer protection laws and similar statutes in California, Florida, Louisiana, Michigan, North Carolina, Ohio and Texas.
Which vehicles are covered by the lawsuit?
The lawsuit looks to cover all vehicles in the U.S. that contain the alleged SDM calibration defect and were manufactured, sold, distributed or leased by General Motors, LLC or manufactured, sold, distributed or leased by Old GM and bought or leased after July 10, 2009.
The vehicle brands under the General Motors corporate umbrella include Cadillac, Chevrolet, Buick, GMC, Saab, Oldsmobile, Hummer and Pontiac. The lawsuit claims that the SDM calibration defect, upon information and belief, exists in all GM trucks and SUVs starting with the 1999 model year.
“This would include, for example, trucks and SUVs such as the Silverado, Tahoe, Astro, and Trailblazer,” the complaint reads. “Discovery will reveal when, if ever, GM discontinued use of the SDM Calibration Defect in its trucks and SUVs.”
How do I get involved in the class action?
There’s generally nothing you have to do to join or be considered included in a class action lawsuit. Those covered by a class action, called “class members,” usually only need to act if and when a suit settles, after which the time will come to file claims for whatever compensation the court might find appropriate.
Class action cases typically take some time to go through the legal process, usually toward a settlement, dismissal or arbitration outside of court. All told, it might be a while before we see a resolution to this suit.
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The complaint can be found below.