(Reuters) -The National Highway Traffic Safety Administration is opening a probe into more than 1.4 million Honda ( HMC ) vehicles sold in the United States over concerns that connecting rod bearing failures in their engines could lead to complete engine failure.

In a letter dated August 20, the regulator said it received 414 reports of the issue in various Honda ( HMC ) and Acura vehicles' 3.5-liter V6 engine.

The investigation covers 2018-2020 model year Acura TLX, 2016-2020 Acura MDX, 2016-2020 Honda Pilot, 2018-2020 Honda Odyssey, and 2017-2019 Honda Ridgeline vehicles.

In 2024, the agency probed 1.4 million Honda ( HMC ) vehicles on reports of serious engine issues following the Japanese automaker recalling 249,000 vehicles in November 2023.

Honda ( HMC ) issued the recall to address a possible manufacturing defect in the engine crankshaft which could cause the connecting rod bearing to prematurely wear and seize, leading to engine failure.

The U.S. auto safety agency said in the August 20 letter it is opening another investigation to more thoroughly evaluate the scope and severity of the potential issue and to fully assess related safety concerns, following the closure of its previous probe.

NHTSA said that the high volume of engine failure reports in vehicles not covered by the previous investigation poses a potential safety risk.

(Reporting by Disha Mishra in Bengaluru; Editing by Mrigank Dhaniwala)