The recall covers 2020 through 2022 model year vehicles including various Avalon, Camry, Corolla, RAV4, Lexus ES250, ES300H, ES350, RX350 Highlander and Sienna Hybrid vehicles and could result in the Occupant Classification System (OCS) sensors not working. It includes 1 million vehicles in the United States.

The sensors ensure air bags do not deploy if a small adult or child is sitting in the front seat. Dealers will inspect and, if necessary, replace the sensors. The automaker plans to begin notifying owners in February about the recall.

Toyota in July 2022 issued a recall for 3,500 RAV4 vehicles in the United states that because of potential interference between internal parts that could cause the OCS sensor to incorrectly detect the occupant.

Frontal air bags have saved more than 50,000 lives in the United States over 30 years, the National Highway Traffic Safety Administration says.

The new sensors were prompted because older air bags deployed the same way for all driver and passengers, causing some injuries and in rare cases even death to children, small adults, and unbelted passengers who were too close to the air bag as it deployed, the agency says.

Earlier, Toyota subsidiary Daihatsu said it will suspend shipments of all car models in Japan and abroad, following news it had rigged safety tests.

The announcement came after an independent panel also found the malpractice dated back to 1989, when the oldest instance was confirmed and reports said the firm faced on-site inspections by government officials.

Toyota, the world's biggest carmaker, expressed its "sincere apologies" over the issue and said it would carry out "a fundamental reform".

The panel was set up earlier this year to probe a safety scandal that emerged in April.

The investigation "found new irregularities in 174 items within 25 test categories" in addition to wrongdoing previously detected in April and May involving door parts and side-collision tests, Toyota said.

With certification being a "major prerequisite" for an automobile manufacturer to conduct business, "our misconduct that surfaced this time amounts to disregard" of that very process, Daihatsu president Soichiro Okudaira told reporters, before bowing deeply to apologise.

In a statement, Toyota also recognised the "extreme gravity" of Daihatsu's neglect, which has "shaken the very foundations of the company as an automobile manufacturer".