Overstressed Airbag Control Units May Cause Seat Belt and Airbag Failure

Millions of vehicles built after 2009 have defective airbag control units manufactured by the company ZF-TRW. An ACU takes information from crash sensors and decides when to deploy the airbags and seat belt pretensioners. But the crash sensor data is being interrupted by experiencing electrical over stress in these ACUs, causing deployment failures in crashes.

At least 8 people in ZF-TRW equipped vehicles have died in crashes where the airbags didn't deploy.

A Massive Investigation ∞

In March 2018, Hyundai recalled the 2011 Sonata after learning about multiple crashes where the airbags had failed. While the automaker knew there was a problem with the ACU, they didn't have a plan for how to fix it. That's a similar scenario Fiat-Chrysler found themselves in a similar recall in 2016.

When details emerged that 4 people had died and 6 others were injured in crashes in Hyundai and Kia vehicles where the airbags didn't deploy, the National Highway Traffic Safety Administration (NHTSA) stepped in and opened an investigation.

During the investigation, NHTSA found that Hyundai and Kia vehicles have the "lowest levels of circuit protection." Hyundai later announced that the ACUs were missing a specific circuit-protecting Schottky diode and added an additional 580,000 cars to their prior recall.

Additionally, Kia recalled 507,000 Forte, Optima and Sedona vehicles after airbags failed.

The investigation has been upgraded ∞

In April 2019, NHTSA upgraded their investigation to an engineering analysis after two major crashes involving Toyota Corollas where the airbags didn’t deploy. There was 1 fatality.

An "engineering analysis" is the final step before a recall, but does not always mean that will be ordered.

Which Hyundais Have Been Recalled? ∞

An Industry Wide Problem ∞

Multiple automakers announced their own recalls as the investigation was ongoing. And while a good number of vehicles have been repaired, it's estimated that ZF-TRW supplied ACUs for roughly 12.3 million vehicles across 10 major automaker brands, including Acura, Dodge, Fiat, Honda, Hyundai, Jeep, Kia, Mitsubishi, Ram, and Toyota.

Multiple massive lawsuits suggest that upwards of 9 million vehicles are still in danger of having airbags fail during a crash.

A full list of vehicles with defective ZF-TRW ACUs ∞

Problem timeline ∞

• September 2016 Fiat-Chrysler recalls about 1.9 million vehicles after airbags failed to deploy in crashes, resulting in 3 deaths and 5 other injuries.
• March 2018 The National Highway Traffic Safety Administration (NHTSA) opens an investigation after airbag failures in Hyundai and Kia vehicles kill 4 and injure 6 more.
• March 2018 Hyundai recalls 155,000 Sonatas with ZF-TRW ACUs.
• April 2018 Hyundai adds an additional 580,000 cars to its recall.
• June 2018 Kia recalls 507,000 vehicles with ZF-TRW ACUs.
• April 2019 Volkswagen recalled more than 34,500 Tiguan and CC vehicles with defective power supply capacitors that cause inadvertent airbag deployments, or cause the airbags to completely fail in crashes. Meanwhile, Honda and Toyota are sued over using ZF-TRW ACUs in Michigan.
• May 2019 A series of lawsuits are filed against Hyundai and Kia.
• July 2019 Volkswagen and Porsche announce recalls covering over 42,000 vehicles.
• August 2019 A massive lawsuit is filed covering 12.3 million vehicles across multiple automaker brands.
• December 2019 A ZF-TRW lawsuit is filed in Quebec.
• October 2020 An even more massive lawsuit is filed for 15 million vehicles across multiple automaker brands.