The National Highway Traffic Safety Administration is looking into reports of engine failure involving more than 1.4 million Honda and Acura vehicles, according to documents recently posted on the regulator’s website.

The engine failures were initially investigated under a previous NHTSA recall in November 2023, after the Office of Defects Investigation received 414 reports of connecting rod bearing problems that were suspected to be the result of a crankshaft manufacturing defect. 

However, NHTSA closed the investigation after it determined the engine failures were outside the scope of the 2023 recall and not caused by “the same crankshaft manufacturing defect that is addressed by Honda in Recall 23V-751,” the latest documents state.

Because of the significant number of reports involving vehicles from Honda and the automaker’s Acura brand, NHTSA said it will open a new investigation “to further evaluate the scope and severity of the potential problem and to fully assess the potential safety-related issues.”

The probe includes the following models and years:

Honda

Acura

• 2016-2020 Acura MDX
• 2018–2020 Acura TLX