general problems of the 2020 Honda Odyssey - part 1

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 NHTSA 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.

The contact owns a 2020 Honda Odyssey. The contact stated that while driving 45 mph, the contact heard a knocking sound coming from the engine, and the vehicle went into limp mode with the low oil warning light illuminated. The contact became aware of a burning odor coming from under the hood, and the vehicle needed to be towed. The vehicle was towed to the dealer, where it was diagnosed and determined that the connecting rod bearings had failed and the engine needed to be replaced. The vehicle was not repaired. The failure mileage was approximately 50,000.

Upon starting my Honda Odyssey, the dash immediately started saying, collision mitigation system problem, adaptive cruise control problem, road departure mitigation system problem, lane keeping assist problem, auto high beam problem.

Stopped at a light, auto idle stop engaged, engine shut off normally. The moment I pressed the gas, everything died — engine and all electronics. I pressed the start button two or three times with no response, then it finally started. It was still in drive. The hazards wouldn't turn on right after, then everything gradually came back to normal.

While automatic idle was on, engine shut down at a red light. Dashboard showed message: put in park. Alternator was fine. Battery fine. I did get the software update but this happened again. This time was able to put in park and was able to start the car. I have to remember to turn off automatic idle to avoid this from happening again.

The engine auto idle system failed at a stoplight. The auto-idle engaged, but when I took my foot off the brake, the engine did not restart. It completely shut down, putting my car in park in a busy intersection. The engine light and an error message flashed briefly but disappeared. I was able to restart the car and drive, however, only after waving several other cars to pass by me. I've noticed recently the restart function lagging, and if I put my foot on the gas too soon, the car lurching and jerking forward (indicating the engine isn't restarting quickly or properly). I recently had a full routine service on the vehicle, indicating battery life is good. No other issues appeared such as overheating.

Vehicle: 2020 Honda Odyssey VIN: [xxx] mileage at time of failure: 155413 component: engine — connecting rod bearingsdescription: my 2020 Honda Odyssey experienced a failure of the connecting rod bearings on 7/30/26, resulting in loud knocking noise. The failure was diagnosed by luis asturias at jim coleman Honda in clarksville, MD. This vehicle falls within the scope of NHTSA's open preliminary evaluation pe25008, which covers 2018-2020 Honda Odyssey vehicles with the 3. 5l j35 v6 engine for this exact failure mode. My dealer declined to cover the repair cost under warranty because no recall has yet been issued. I am filing this complaint to document my experience as part of the ongoing federal investigation. Repair cost estimate: $4573. 00. The vehicle is not driveable without this repair. Thank you for your prompt attention,[xxx] information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).

The vehicle is a 2020 Honda Odyssey. A recurring and dangerous safety failure occurs involving the auto idle-stop system. With the system enabled and the vehicle at a complete stop, the engine shuts off as designed. However, upon depressing the brake pedal to resume driving, the engine severely struggles to restart and completely fails. Simultaneously, the vehicle immediately and automatically shifts itself into park, and the entire dashboard display illuminates with all available warning icons and messages. This malfunction creates an immediate, high-risk safety hazard. When the incident occurs, I am trapped, locked in park, in live traffic lanes, sometimes at busy intersections or during left-hand turns. It is impossible to shift back into drive or quickly restart the engine. I am forced to remain stationary in traffic for multiple minutes until the system allows me to cycle the ignition completely off and then back on to attempt a full restart and shift back into drive. This leaves my vehicle, my passengers, and other drivers vulnerable to rear-end collisions.

Multiple times the engine has totally shut down due to the auto idle stop system power loss. I have had the battery replaced a couple times and had the Honda dealership do the software update and I'm still having issues. This is a major safety issue as the car unexpectedly shuts down and takes a minute or so to get started again causing traffice backups.

While stopped at a traffic light my vehicle went into auto engine idle stop mode. When the light turned green, I removed my foot from the break, but the engine failed to restart. I had to shift the car to park and fully restart the engine.

The automatic engine shut off at stop doesn't always restart engine when moving again. This has happened several times where the engine doesn't restart after the engine shut off is engaged. This is the same issue as reported in NHTSA action number: ea25004.

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.

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.

The contact owns a 2020 Honda Odyssey. The contact stated that while reversing at an undisclosed speed, the vehicle stalled. No warning lights were illuminated. The vehicle was towed to a dealer where it was diagnosed and it was determined that the engine needed to be replaced. The vehicle was not repaired. The manufacturer was notified of the failure. The failure mileage was approximately 59,000.

The contact owns a 2020 Honda Odyssey. The contact stated that the vehicle made an abnormal ticking sound while depressing the accelerator pedal, and the engine made a loud sound. There was no warning light illuminated. Upon investigation, the contact related the failure to NHTSA action number: pe25008 (engine). The vehicle was taken to the local dealer, where it was diagnosed and there were metal shavings found in the engine oil. The dealer determined that the engine needed to be replaced. The vehicle was not repaired. The manufacturer was contacted and confirmed that there was no recall or warranty coverage for the repair. The failure mileage was approximately 85,000.

Our Odyssey is equipped with idle stop. Sometimes when idle stop engages, the engine won't start again afterwards. We need to turn the car off completely, and then try again. Usually it turns on after doing so. We try to always turn off the idle stop when we start up the vehicle, but sometimes forget. This hasn't led to an accident yet, but has led to some angry vehicles when we can't move when a traffic light turns green. To be clear, this was not an isolated incident, but happens somewhat regularly if idle stop isn't turned off. Honda dealers have told us they don't have any fix, and have recommended that we could purchase a third party "idlestopper".

Following replacement of the small block in Dec. 2025 for bad pushrod bearings. The vehicle ran for 3000 miles, before the engine seized up again while driving at 50 mph. The vehicle came to a stop in the travel lanes and could not be moved due to engine failure. Upon having the vehicle towed back to the dealership for inspection and repair, they found that the #3 cylinder had both valves broken and metal pieces shavings found in the engine. The dealer claimed that this was not related to the previous replacement of the small block as they did not work on the headers. However I believe the original issue of the bad pushrod bearings caused poor oil flow to the headers and the valves were already worn before the Dec. 2025 engine seizure. The dealer has now replaced the small block (for a 2nd time) headers, intake manifold, injectors and timing chain.

Car would randomly die while I was driving, causing my children and I to be in severe danger in the middle of a busy road multiple times.

My wife started hearing a knocking sound while driving, coming from under the hood. I opened the hood while the engine was idling and could tell the sound was coming from inside the engine. Checked the oil level and it was in the operating range and looked clean. I had just changed the oil and filter 08/2025. After that we immediately drove it to the Honda dealer where we purchased the vehicle and the service manager heard the noise, checked for recalls, but could only find the recall for the 2019 Honda Odyssey [xxx] the service manager called in one of his mechanics to listen to the noise in the service manager bay and he said, "sounds like a bad rod bearing". They then took the vehicle to inspect it further in the mechanic's garage, but as they were pulling it into the bay the engine complete seized up. The vehicle only has 68k miles on it, but now its beyond the warranty period. I was also told by the dealer when I purchased it, that it and the 2019 are identical, so why was the recall issued for the 2019 Odyssey, but not the 2020 model? I'm reading lots of similar reports of this same exact issue with the 2020 model from Honda forums and on youtube posts. This engine problem is clearly larger than the initial recall that was issued in 2024. Information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).

Connecting rod bearing failure at 105,000 miles, even with full recommended and documented service history.

I was driving with family to a family trip up to the mountains to enjoy the snow when at a rest area I noticed the Odyssey just had a slight delay to turning on before continuing the trip. No lights no signs of anything going wrong. As we continued our trip back onto the freeway on a curvy road and night time the Odyssey didn’t want to shift gears wouldn’t speed up for freeway traffic. Immediately started pulling over. The Odyssey would make like jerking movements decided to call the tow truck and it quickly escalated to draining the battery. After being at the tow facility for one night it completely didn’t want to even turn on next day. Put a new battery and still drains the battery. I took it to Honda service to run a diagnostic and they come back saying the engine is seized. No lights no signs didn’t see this coming with only 87,000 miles. With a black screen displaying electrical issue at times.

In the past six months the Honda "auto-start" feature has caused my vehicle not to restart while stopped at an intersection. Honda needs to immediately recall all gen 5 vehicles that use the auto-start feature and permanently disable (or give an option to disable) this useless, safety-affecting "feature". Thank you.

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 NHTSA to require Honda to provide an effective, long-term solution to ensure the safety of Odyssey owners.

The auto idle start when I am at a red light it will turn off and put it in park. I have to restart the van and put it back in drive. I believe this to be a safety issue. I have my kids with me and its dangerous. I would like to know what can be done and why hasn't this been a recall. I have to remember to push the auto idle button each time I get in to drive otherwise im afraid ill get stranded at an intersection. Its been going on for at least a year and the dealership thought it was the battery we have replaced the battery so that is not the issue.

The contact owns a 2020 Honda Odyssey. The contact stated that while driving at an undisclosed speed, the vehicle inadvertently lost motive power. The contact was able to coast to the shoulder of the roadway, where the vehicle failed to restart. No warning lights were illuminated. The vehicle was towed to the dealer, who diagnosed a failure with the connecting rod bearings, resulting in damages to the engine, causing the engine to seize. The contact was informed that the engine needed to be replaced. The vehicle was not repaired. After investigating the failure, the contact related the failure to NHTSA campaign number: 23v751000 (engine and engine cooling), but the VIN was not included. The manufacturer was not notified of the failure. The failure mileage was 130,000.

My can intermittently fails to start after the auto idle start system has engaged. I am stopped at a light on a busy road. When the light turns the car tries to start but fails. Some times it is able to start but I get warnings that multiple systems had an issue or at disabled. Other times it fails to start completely and I have to cycle the power off and open my driver door before I can start the car. This has been happening for more than a year and the battery has already been replaced.

My car went completely dead while stopped in traffic on a busy street. My kids were in the car and thankfully I was able to crank it by pressing the start button. This issue has already been “fixed” and the dealership “cannot replicate”.

Engine recently began making noise and the car was taken into Honda. The dealer checked engine components to find the cause and recommended that we remove oil pan to inspect the issue because they assumed it might be engine bearing related. Before we could schedule the service I was driving with my family on the highway when we heard a loud noise and complete loss of power. I was able to move over avoiding other cars to reach the shoulder and come to a stop. The car would not start or go into any gear. Car was towed to shop. What component or system failed or malfunctioned, and is it available for inspection upon request? the car has not been inspected yet. Currently at shop being evaluated. Has the problem been reproduced or confirmed by a dealer or independent service center? engine was making noise at the dealership when it went for service. There was no concern made by dealer stating car was unsafe to drive. Has the vehicle or component been inspected by the manufacturer, police, insurance representatives or others? was inspected before the car broke down, but currently being evaluated by local shop. Were there any warning lamps, messages or other symptoms of the problem prior to the failure, and when did they first appear? there was an unknown noise coming from the engine, and dealer stated they needed to remove oil pan to diagnose the noise but stated it could be bearing related. The dealership did not say the car was unsafe or should not be driven. Before we could look into the issue more the car broke down on the highway.

Honda has been serviced at Honda of ames #190 since 2022. 2023 - issues with the engine stalling when it goes into idle mode at a stop. September 2023 – contacted Honda of ames, IA dealer. They indicated it’s the battery which will need replaced. Took the car to interstate battery on 9/26/2023 where it tested at 12. 5 volts out of possible 12. 6 volts. Then took the car to dealer who insisted it was an issue with the battery. Replaced battery for $391. Problem continued. In 2024 there was a recall a known issue with the engine idle functionality requiring a software update. Took the vehicle in for the software update. Complained to the dealer that I unnecessarily spent $390 on new battery when that wasn’t the issue. They refused to refund any money. Problem persisted. On 5/21/2025 the car was brought into dealership for 100k service. I complained again that the auto-idle feature still stalling. Was told that it's not a universal known problem, they don’t have a fix that he’s aware of other than to check the battery. I explained we’ve been through this before and brought up sept 2023 battery situation. He stated that the quick/handheld battery testers are not reliable; repair shops have “the big testers in the back” that are more reliable – that is what they will test my battery on. I asked if they could turn off the feature permanently and was told no. When car was ready I was told that the battery life tested fine. They did a software upgrade and I will need to drive it and just see if the stall issue continues. He repeated that it’s not a “universal known problem” and there was nothing further he could do. 7/5/2025 – the auto-idle has stalled twice since the service on 5/21/2025. Stalling in an intersection, at a red light, bottom of an off-ramp, etc. I s a serious and highly concerning safety issue.

High pressure fuel pump makes loud noice. Fuel line vibrates. Check engine light on, shows error code low fuel pressue.

On June 23, 2025, while driving my wife to the rdu airport, our Odyssey's engine failed to restart after an auto idle stop (ais) at a busy intersection in greensboro. Instead of starting, the dashboard displayed a collision mitigation system problem alert, the drive ("d") indicator light started flashing, and then the dashboard displayed a "shifting to park: apply brake pedal" message. We were stranded at a busy stoplight, at the front of a dedicated left-turn lane, unable to drive or shift to park as instructed. The only way to resolve the issue was to hold the start/stop button for several seconds to shut the vehicle off. And the vehicles behind us had to swerve around us because our malfunctioning vehicle was blocking the lane. This problem has recurred semi-regularly since June 23, forcing us to manually disable the auto idle stop feature on every drive to prevent being stranded in traffic. An independent mechanic found no stored diagnostic codes but identified relevant Honda technical service bulletins (23-008 and 23-009) addressing similar ais failures. A Honda service center misdiagnosed the issue as a faulty battery, but subsequent testing by the independent shop confirmed the battery was in excellent working order. The actual auto idle stop malfunction remains undiagnosed. The vehicle and its auto idle stop system remain available for inspection. This issue appears to be part of the ongoing NHTSA engineering analysis ea25-004.

Subject: urgent vehicle safety concern – sudden malfunction and safety risk on [xxx], at approximately [xxx, I experienced a traumatic incident when my vehicle unexpectedly malfunctioned while I was driving home. After making a left turn on a green signal from [xxx] toward the community, the car suddenly stalled. By god's grace, I managed to cross woodbridge avenue before stopping, avoiding a major traffic obstruction. However, it came to a complete stop in the middle of the street, creating a hazardous situation. After a brief pause, the car moved approximately 10 yards before stopping again, becoming completely immobile in the middle of a public road. Attempts to jump-start the battery failed. All warning lights turned on, but the engine would not start. The vehicle could not be restarted or moved under its own power. 911 was called, and police responded promptly to the scene. With the assistance of my wife, police officers, and local neighbors, a tow company was called to remove the vehicle from the roadway. It was then towed and parked in a nearby lot. This incident was highly traumatic and posed a serious threat to my safety, my family's safety, and the safety of the public. Diagnostics and expert assessments indicate the issue may be related to a manufacturer defect, which is deeply concerning given that this is a new vehicle. At this time, the vehicle is no longer drivable. I am seeking urgent assistance to resolve this matter with the manufacturer and to ensure that other consumers are not exposed to similar risks. Information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).

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 NHTSA 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).

The idle start stop feature constantly doesn’t work. When stopped at a light or stop sign the engine will turn off and when I release the break it is supposed to reengage the engine. Instead it stalls out causing me to have to put the car in park and restart the car. There have been several incidents where this is during rush hour traffic causing traffic jams. Sometimes I have to wait a few minutes before it will actually turn over. The car is 5 years old and I have had the replace the battery twice and I have been told that this feature puts a lot of pressure on the battery. Never can the dealership recreate the issue.

The contact’s daughter-in-law owns a 2020 Honda Odyssey. The contact stated that while his daughter-in-law was driving at an undisclosed speed, there was an abnormal sound coming from the engine compartment. The contact stated that an unknown flashed on the instrument panel. The contact stated that the sound had become louder over time. The vehicle was taken to a certified mechanic who diagnosed vehicle with engine failure and stated that the engine needed to be replaced. The vehicle was not repaired because the vehicle was no longer under warranty. The manufacturer was not made aware of the failure. The failure mileage was approximately 84,688.