2020 Honda Odyssey: start-stop system problems

Filed Nov 8, 2026 · Electrical, Fuel system · MN

Auto-stop/start function will randomly fail. Also appears to cause other electrical issues when starting up; complete loss of electrical power.

Filed Oct 23, 2026 · Electrical, Engine · GA

My 2020 Honda Odyssey EX-L intermittently fails to restart after the Auto Idle Stop feature shuts the engine off at a red light or stop. This has happened probably 10 times in the past 6 months. In order to start the engine, I must recognize that the engine isn't starting, turn off the vehicle, and turn it back on, often 2-3 times before it actually starts. This leaves the vehicle stopped in a traffic lane at an intersection with traffic trying to pass, which creates a risk of rear-end collision or cars trying to pass me. Cars have gotten into near misses trying to pass me while my vehicle is inoperable. I have no warning lamps or messages before it happens. History: The dealer performed Honda’s idle-stop software update (service bulletin 23-008) in November 2024 at about 63,100 miles. The problem continues. The battery was replaced in December 2022, and the dealer’s October 2026 inspection rated the battery “Good.” (as did a second independent auto shop). At 93,331 miles in October 2026 the dealer documented the complaint, charged a diagnosis fee, and recommended replacing the starter motor at a cost of $954.53 plus a diagnostic fee of $184.95. I contacted Honda, which opened a case and offered only partial goodwill coverage. I am not aware of any additional recall or warranty extension covering this on my model. This appears to be the same condition as the federal safety agency investigation EA25004 (no restart after auto start/stop engages), which covers 2018-2025 Odysseys. The failure persisting after the software update matches the investigation’s finding that complaints continue after Honda’s countermeasures. I can share vehicle inspection records if helpful.

Filed Jun 23, 2026 · Electrical, Engine · TX

The auto Start/Stop feature doesn't work as needed. It will randomly lurch, turn the car off make me put it in park and then have me restart it. Sometimes the car does not start right away and I am stuck on the road until it decided when and if it will restart. Myself and my family of 5 are not stuck in the road scared of getting smashed into by other drivers unaware that we are stopped or anticipating for us not to be stopped in the middle of the road. I really dont want my family to go to the hospital or die because of this nonsense. Sometimes it doesn't fully shut off but will give error warnings like collision mitigation assistance even though there is nothing for it to mitigate. There are no cars around me and it shouldn't have done this. This has been happening for some time and only happens haphazardly meaning I can't always have the dealer identify or diagnose the issue. Then when I brought it to the dealer, they told me it was because of a power liftgate module error. Which was not true and didn't solve the issue.

Filed Jun 15, 2026 · Electrical, Engine · SD

Our vehicle has stalled at stop lights several times over the past 6 years. The auto stop/start feature seems to fail. The vehicle will shut off but when you repeat the brake it will not restart and the vehicle will die completely. You have to put it in park, wait a few seconds and try and restart. Additionally it has completely died at gas station after turning it off to refuel. When you go to start the vehicle it will be completely dead, zero power. We had to have it jump started. The battery has been replaced twice and was testing normal at the dealership. Not a battery issue. Honda acts like this is unheard of but our own research indicates it is a common well known problem with new Odyssey models.

Filed Jun 13, 2026 · Electrical · CA

the federal safety agency Complaint Narrative – 2020 Honda Odyssey VIN: [XXX] Beginning in 2021, the vehicle experienced repeated starter and idle stop system failures, including: •delayed starting •failure to restart after idle stop •multiple warning lights •intermittent no start conditions •repeated battery failures The earliest documented complaint (Culver City Honda, March 25, 2021) states: “When using the auto start/stop feature the vehicle will have multiple warning lights. Sometimes will struggle to turn back on.” These symptoms continued for several years despite multiple dealer visits, battery replacements, electrical diagnostics, and software updates. In late 2025, the starter failed completely and required replacement at a cost of $1,890.25. The failure of the idle stop restart system poses a safety risk, as the vehicle may fail to restart in traffic after stopping at an intersection. Honda has refused to provide any written response regarding the issue. I am submitting this complaint so the federal safety agency is aware of the repeated failures and the potential safety implications. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Oct 7, 2025 · Electrical, Engine · VA

Honda Odyssey Idle Stop system failure Vehicle: 2020 Honda Odyssey (Elite) Incident description: While driving, the vehicle's "Idle Stop" system engaged as I came to a complete stop at [e.g., a traffic light, intersection, stop sign]. The engine shut off as designed, but failed to restart automatically when I released the brake pedal. This left my vehicle stalled and disabled in the middle of [e.g., an intersection, a lane of traffic] with no forward power. I was scared as there were lots of cars behind me in the intersection. This has happened over a dozen times. Safety risk: This failure created an immediate and dangerous safety hazard. My vehicle was a risk for being rear-ended by traffic from behind, and my family was stranded in a vulnerable position. The vehicle was unable to move out of harm's way, and I had to put the vehicle in park and manually restart the engine. This is unacceptable for a system designed to work seamlessly and automatically. Additional information: This is not an isolated incident. The auto start-stop failure has occurred multiple times since March 2025. The system failure has put me and my passengers in a position of significant risk multiple times. Failed component: The vehicle's "Auto Idle Stop" (AIS) system, which failed to restart the engine after it was automatically shut off. Resolution: An immediate and permanent recall is necessary to address this dangerous defect. Existing service bulletins have not corrected the problem. I urge the federal safety agency to require Honda to provide an effective, long-term solution to ensure the safety of Odyssey owners.

Filed Mar 27, 2025 · Electrical, Engine · VA

I am filing this complaint regarding a serious safety defect that persists in my Honda vehicle following Honda's PGM-FI Idle Stop software update. Recently, I experienced a dangerous incident on [XXX] outside Washington, DC. My vehicle completely stalled in heavy traffic, leaving me unable to start my car on the highway. The vehicle would not restart for approximately one minute, creating a significant safety hazard as traffic moved around me. Of particular concern was that during this incident it is not clear whether or not the airbag system would deploy since the car was off. This is a major safety issue and, reviewing complaints online, I am not the only customer to experience this, despite having received the software update. This is not an isolated incident. The vehicle's auto start-stop feature continues to malfunction, repeatedly shutting down when it goes into idle. This issue is also causing significant battery drain, making the vehicle increasingly unreliable and unsafe to operate. Worse, Honda indicates that this feature can act up when the battery is low, but the feature itself drains the battery. You can turn the feature off every time you get in the car, but this is not a fix. I have been informed by Honda there is no way to permanently disable the feature. I strongly urge the federal safety agency to investigate this matter. The current recall repair has proven insufficient to resolve the safety defect, and the malfunction creates unacceptable risks for me and my family. This issue requires immediate attention to prevent potential accidents and ensure the safety of all road users. Please require Honda to implement a repair that allows consumers to permanently disable this feature. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Nov 11, 2024 · Engine · OH

Several times over the last 18-24 months my van has 'stalled' after the auto engine start/stop feature restarts my car. This has mostly happened while at stop lights/signs, or idle. However, it has happened twice while driving, my car will just die and slow dramatically. I have been able to restart by pushing the start/engine button. There has been two times where restarting (while idle) has not worked. Most recently it happened while at a stop light. when the light turned green I went to accelerate and the van would not move, all the dash lit up, and there was no power to the engine. It took several minutes to get the van restarted, holding up traffic and causing me panic and fear that I could be hit.

Filed Aug 18, 2023 · Brakes, Driver assistance · IN

This event happens intermittently, and has occurred approximately 4 times. When the issue occurs it happens as follows: 1. Vehicle comes to a complete stop, and driver's foot has depressed brake pedal 2. Vehicle automatic start/stop feature turns off engine. 3. Driver lifts foot off pedal, begins to apply pressure to gas pedal. 4. Vehicle automatically re-starts engine 5. Vehicle starts to move forward, and then lurches - it feels like the brakes are being applied by the vehicle independently from the driver's action. 6. Alerts start appearing on the dashboard - a message that the Forward Collision Warning System has been disabled and the "BRAKE" light starts flashing for 30 seconds to a minute afterwards. 7. Vehicle then starts to move forward without issue, Collision System message goes away, but BRAKE light on instrument cluster continues to flash for a period of time. This issue presents a safety risk as the vehicle does not respond to driver's input as expected when this issue occurs, appears to brake on its own. Interferes with a driver's ability to move through an intersection after stoping. I have taken the vehicle to a Honda dealership (Penske Honda, Indianapolis Indiana) and they were unable to replicate the issue and did not find any stored error codes in the vehicle comptuer.

Filed Mar 27, 2023 · Electrical, Engine · TX

Auto engine idle shut off issue and yes it is available for inspection. Upon exiting stop/start events(auto shut off at stop signs/lights/parking lots), engine does not restart. instead, it shifts into park, lights up all instruments on display panel, and requires a manual restart. vehicle is dead until restarted, posing a hazard to occupants/oncoming traffic. This has happened to me 3 times over the last two weeks. Didn't document date of 1st incident. 2nd incident was 3/22/23. 3rd incident was 3/25/2023. Immediately taken to dealer service center for repair. Dealer told us they couldn’t replicate the issue, that there are no codes, and no service advisories. We were told there was nothing they could do and to just turn off the feature when driving. The only one to inspect the vehicle was the dealer service center. No warning at all. Car just doesn't start and driver is left sitting and helpless in active traffic until the car can be restarted.

Filed Oct 12, 2022 · Engine · TX

Several times the van has failed to restart from an idle stop/start at a red light and in the middle of stopped traffic. Several attempts to restart the van fail (van doesn’t even try to start) normally after a few minutes with the van back in park it will start again. Very dangerous to be frequently left stranded in the middle of the road. Frequently when the van does successfully take off from a idle stop, you can tell it struggles and just barely is able to resume.

Filed Sep 21, 2022 · Driver assistance, Engine · NC

When the automatic start/stop feature turns the car off when the brake is fully depressed the Car will sometimes not restart as designed. Further, it is sometimes accompanied by the forward collision warning light coming on and shutting the car off.