DETROIT (AP) - U.S. auto safety regulators have expanded an investigation into malfunctioning airbag controls to include 12.3 million vehicles because the bags may not inflate in a crash.

As many as five deaths are blamed on the problem. The probe covers parts made by ZF-TRW that were installed in Toyota, Honda, Kia, Hyundai, Mitsubishi, and Fiat Chrysler vehicles from the 2010 through 2019 model years. Government documents say electrical signals can interfere with a circuit that monitors crash sensors. The interference can damage the circuit.

Investigators recently found two serious crashes involving 2018 and 2019 Toyota Corollas in which the airbags did not inflate. One person was killed.

The agency opened an investigation in March of 2017 involving Hyundais and Kias. Four fatalities were reported at that time.