A US investigation into airbags using TRW (absorbed into ZF) control units now includes millions of additional cars, according to US media reports.
Documents from the National Highway Traffic Safety Administration (NHTSA) showed it was examining an additional 12.3m vehicles but had not issued a recall, Newsweek.com said.
The airbags may have defects that prevent them from deploying, the report added.
“The Office of Defects Investigation (ODI) is expanding the investigation to include the equipment supplier and vehicle manufacturers (OEMs) using this unit,” an NHTSA document said.
The report said vehicles involved were made by automakers including Fiat Chrysler Automobiles, Honda, Hyundai, Kia, Mitsubishi and Toyota.
The NHTSA said some vehicles have TRW (ZF) airbags which could fail during a crash event.
“These control units may suffer electrical overstress due to harmful signals (electrical transients) produced by the crash event, causing the unit to stop working during the crash,” an NHTSA document said.
Airbag control units may be faulty so don’t sense a vehicle crash in order to deploy the necessary airbags.
Newsweek said there were two “substantial frontal crash events,” one of which was fatal, in which the non-deployment was suspected to be due to this failure. The issue could also lead to the failure of seat belt pretensioners in a crash as well.
The report noted the expanded investigation comes after months of announcements regarding exploding Takata airbags. The inflators concerned are involved in tens of millions of recalls.
ZF, which acquired TRW Automotive in 2015, said in a statement cited by Autoblog it is committed to safety and was cooperating with NHTSA and automakers in the investigation.