Airbags are back under the microscope

Faulty electrical signals are under the microscope in an expanding U.S. safety investigation of airbag malfunctions that could affect 12.3 million vehicles.

NHTSA last week said in a document it was broadening its year-old investigation of an airbag problem that appears to be caused by "electrical overstress" — possibly involving system wiring — that may be to blame for failed deployments in crashes that resulted in at least eight deaths in the U.S.

The investigation, which initially covered 425,000 vehicles, has not reached any conclusions, and the safety administration has not ordered a recall.

But the scope of the new question — now involving vehicles from FCA US, Hyundai-Kia, American Honda, Toyota Motor and Mitsubishi — is hauntingly reminiscent of the industry's enormous and costly Takata airbag recall of the last six years. There is no connection to the problems with Takata airbags, however.

The expanding investigation also is a troubling reminder to the auto industry and consumers that, despite nearly 30 years of use, airbags are still not the flawless safety technology that many drivers assume.

NHTSA said it's focused on airbags manufactured by U.S. supplier TRW and the German technology leader that acquired TRW in 2015, ZF Friedrichshafen. The vehicles targeted by the investigation are from the 2010 through 2019 model years.

ZF, in a statement, said it is "committed to motor vehicle safety."

"ZF proactively notified NHTSA and vehicle manufacturers following initial observations of electrical overstress damage to airbag control units in certain vehicles in the field and has worked diligently with them since it was first discovered to understand this complex issue. ZF continues to cooperate with NHTSA and our customers in the investigation," the statement said. The company declined to comment further.

Airbags have been a tender spot for the industry since the Takata airbag inflator recall began in 2013. That product failure was blamed for more than two dozen deaths worldwide, ensnared more than 41 million vehicles, bankrupted Japan's Takata Corp., involved more than 100 million suspect inflators, entangled retail parts and service lines and infuriated many consumers who are still waiting for replacement parts.

But the TRW/ZF question under investigation bears little resemblance to the Takata ordeal, says Scott Upham, a veteran analyst of the industry's interior and safety segments. He believes the culprit will turn out to be on the electrical side of the airbag system — possibly even in the wiring that connects the airbag with the vehicle's crash detection sensors.

According to the NHTSA statement, a crash involving the vehicles under examination may "produce harmful signals on the sensor wiring capable of damaging" the circuits that monitor crash signals. The airbag control unit is in the passenger compartment, connected by wires to sensors in the front of the vehicle.

"There is a lot of complexity in these systems," said Upham, CEO of Valient Market Research in Philadelphia. The airbag control unit "commands all the different firing circuits in concert. The airbags have to go off, the seat-belt pretensioners have to go off in a certain sequence, and sometimes there are seat adjustments and other pieces involved, with all of it occurring within 20 milliseconds. When the wiring that connects it all doesn't work exactly right, it's a problem."

But replacing wiring or other associated electrical pieces would be simpler and less expensive than replacing a vehicle's airbag inflators, he said.

"In a worst-case scenario, even if this results in a recall of 12 million vehicles, 12 million is nothing to sneeze at, but it's nowhere near what we went through with Takata," Upham said.

The nightmarish problem in the Takata recall was a flawed inflator that had a risk of exploding and injuring or even killing vehicle occupants with shrapnel. To fix it, automakers needed millions of replacement inflators, and Takata lacked the capacity to provide them, Upham pointed out.

Further complicating that situation, by the time of the recall, Takata already had retired the part in question and moved on to a newer design. The tooling to manufacture the old inflator was no longer in use and had to be retrieved to allow Takata's competitors to help manufacture enough parts to service the recall.

But Upham pointed out that NHTSA's analysis is incomplete, so it's not yet known what the root cause of the problem is and whose problem it will be to fix.

Should NHTSA's engineering analysis conclude that the issue stems from a wiring problem, there are some two dozen automotive wiring suppliers that could step up to address a large recall, should one be required.

"If it turns out to be a Tier 2 issue," Upham said, "there is plenty of Tier 2 capacity to address it."