Toyota Motor Corp is recalling 550,007 vehicles in the United States as a faulty seat-back mechanism may fail to lock, increasing the risk of injury, the National Highway Traffic Safety Administration (NHTSA) said on Wednesday.

The recall includes certain 2021–2024 Highlander and Highlander Hybrid vehicles because the second‑row seat backs may not lock into place during adjustment.

Dealers will replace the return springs in the seat-back recliner assemblies at no cost to owners, NHTSA said.