2021 Honda Odyssey: start-stop system problems

Filed Sep 28, 2026 · Electrical · SC

Auto start stop not restarting while stopped at intersection. Needed to manually turn car off and back to restart.

Filed Jun 29, 2026 · Electrical, Engine · TX

When stopping at an intersection the engine fails to restart after stopping due to the auto start/stop feature. The car tries to start and stalls and dies, and must be completely turned off before it will restart. This has happened 5-6 times now. There are no warning lights on the dash.

Filed Jun 6, 2026 · Electrical, Engine · PA

What component or system failed or malfunctioned, and is it available for inspection upon request? The Auto Start/Stop function only works intermittently on our 2021 Honda Odyssey. Occasionally, when the Auto Start/Stop function does shut off the engine when the vehicle is at a complete stop, the engine fails to restart on its own. The vehicle is available for inspection upon request. How was your safety or the safety of others put at risk? This malfunction occurs intermittently and without warning when the vehicle is at a complete stop in traffic. The vehicle cannot be driven under its own power in this condition, often leaving it disabled in a traffic lane with other vehicles stuck behind and/or passing by at normal travel speeds. As such, it endangers both the occupants of my vehicle and the other vehicles in the vicinity. Has the problem been reproduced or confirmed by a dealer or independent service center? Yes. My local Honda dealership acknowledged the problem and completed a PGM-FI software update. However, this update did not correct the issue, and Honda refuses to take financial responsibility for the repairs necessary to correct the problem. Has the vehicle or component been inspected by the manufacturer, police, insurance representatives or others? Yes. The following timeline details my interactions with my local Honda dealership regarding this issue: 4/13/23 - The dealership inspected the vehicle and claimed the Auto Start/Stop system was "operating as designed"; 9/6/24 - The dealership completed a PGM-FI update as directed by a Honda product update campaign; 2/12/26 - The dealership inspected the vehicle, suggested battery replacement (which tested good on 3/3/26), and if still not corrected, advised replacement of the starter at my expense. Were there any warning lamps, messages or other symptoms of the problem prior to the failure, and when did they first appear? The problem has occurred without notice since purchase on 3/11/21.

Filed May 12, 2025 · Electrical · 32,000 miles · NY

The contact owns a 2021 Honda Odyssey. The contact stated while at a stop light and depressing the brake pedal, the engine turned off; however, once the accelerator pedal was depressed, the Auto START/STOP failed to operate as intended. The contact turned off and restarted the vehicle and the vehicle started to work as intended. No warning light was illuminated. The vehicle was not taken to a dealer or independent mechanic to be diagnosed. The vehicle was not repaired. The manufacturer was not notified of the failure. The approximate failure mileage was 32,000.

Filed Mar 31, 2025 · Electrical · NH

Car has completely shut off when the auto start/stop engaged after coming to a stop at a red light/stop sign on multiple occasions. Everything shut completely off, no radio, lights, etc. Had to push the start button multiple times to turn the car back on. Please investigate as I have read of this happening to many other people with 0 solution from Honda. This is a defect and should be recalled/fixed.