The NHTSA (National Highway Traffic Safety Administration) in the U.S. has opened an investigation into the start/stop system found in Honda and Acura models. In total, 2.2 million vehicles could be affected by the issue being looked at.

A number of Honda/Acura owners have reported that the engine does not restart on its own after shutting off by itself after a complete stop, for example at a traffic light.

The NHTSA is focusing on models equipped with the brand's 3.5L V6 engine. The models concerned are the following:

Honda is aware of the issue, and as early as January 2023, it published technical service bulletins addressing it. An initial repair involved a software update managing fuel injection programming, followed by the replacement of the starter and its relays. A valve adjustment was also planned.
The repairs carried out evidently didn’t eliminate the problem. The NHTSA has continued to receive reports of engines staying off when they shouldn’t.

Clearly, a vehicle not restarting automatically when a light turns green can represent a danger for the driver and other motorists. A distracted driver behind could easily rear-end the stalled vehicle.

In this regard, the NHTSA recounts the complaint filed by the owner of a 2016 Honda Pilot, who reported that that the issue is continuous and that they have been caught several times in the middle of an intersection because the stop/start system is constantly leaving the vehicle stalled rather than restarting it.

A more comprehensive technical analysis of the start/stop system will be carried out in the coming weeks. Honda and the NHTSA will work together to find an effective and permanent solution to this recurring problem.

As well, Honda in the U.S. has extended the warranty to 10 years with unlimited mileage for vehicles that have not been repaired and have not benefited from a software update. We can probably expect the same for vehicle owners in Canada.

Take note that for the moment, this is an investigation and is not yet at the stage of a recall. That could still happen, depending on the results of the investigation.