The National Highway Traffic Safety Administration (NHTSA) just opened an engineering analysis into a potential safety defect affecting more than 2.2 million Honda and Acura vehicles. The issue involves the Auto Start/Stop system, which may prevent the engine from restarting after coming to a complete halt at intersections or traffic lights.

The investigation covers multiple models, including the 2016-2025 Honda Pilot, 2018-2025 Odyssey, 2019-2025 Passport, 2020-2025 Ridgeline, 2015-2025 Acura TLX, and 2016-2025 Acura MDX. Drivers already filed 1,348 complaints, including reports of four crashes and two injuries. Some said they needed a jump start to get their vehicle running again after an Auto Start/Stop failure.

NHTSA first opened a preliminary evaluation in June 2022, focusing on 2016-2019 Honda Pilot models. By January 2023, Honda issued service bulletins addressing the problem in several affected vehicles. The recommended fix included a software update and, if necessary, replacing the starter assembly, relays, and performing a valve adjustment. Honda also extended the warranty to 10 years with unlimited mileage for vehicles requiring parts replacement.

Still, complaints about the issue persist, with some owners stating that Honda’s fix didn’t resolve the problem. As a result, the NHTSA just escalated its investigation to an engineering analysis, which will help determine if a broader recall is needed. The agency will continue collecting data on the effectiveness of Honda’s repairs and any additional risks posed by the defect.

Owners of affected models should monitor NHTSA’s website for updates and contact Honda if they experience issues with the Auto Start/Stop system.