general problems of the 2020 Honda Odyssey - part 1

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 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.

It happened twice this month already. Once while driving, the car lost power (as if engine was never turned on), and the gear changed to n so I tried to slow down, then the power came back on, and then I was able to shift to d and continue my trip. Second one happened this morning. It was on auto-shutting idle position and when I put my foot on the accelerator, it completely lost power again (I recently changed the battery and tested in the afternoon and all working properly).

I was driving with cruise control on and a car pulled in front of me and hit the brakes. My car reacted by hitting the brakes hard and the engine tried to recover but hiccupped and lost power and engine light flashed at me. I pulled over and when I started the car again there was a rattle that would get faster if I pressed the throttle. I was able to get back on the road and the throttle rattle was still there and now it started saying engine oil low. I pulled over, checked dipstick and it was fine. Engine oil low light continued to flash, so I went to a oil change place to have them look and change the oil and they reported nothing wrong. I left and continued driving and the rattle noise was still there, engine oil low was still there. Then I heart a loud pop and griding noise, lost all power and had to pull over. This time the car was dead. I had it towed to a mechanic who said had to be an internal defect in the engine from the factory.

Several engine failures, starting one month after purchase in September 2020. Multiple system failures (all on video) leading to very poor acceleration and operation. No compression in engine and only able to go 20 mph. White-allen Honda made four attempts to solve the matter over the course of two years. The dealer has had the car a total of 120 days. Then end of December 2024 then engine began making a knocking sound and I was told it needed at new engine, to the tune of $10,000. 00. Then I see a recall for a similar issue but only up to 2019 Odysseys. Please help find resolution for this.

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.

Unknown. Auto engine idle stop was enabled when the vehicle was at a complete stop. Upon disengaging, the engine stalled and took a couple minutes to restart the vehicle. The vehicle was located in a highway that caused traffic delay and safety concerns. This has happened more than once.

I was stopped at a light at a busy intersection and when I went to drive when the light turned green, my van did nothing. It had turned off the engine when I stopped at the intersection. I tried to switch gears and it wouldn’t change. I was kind of panicking because I was holding up a ton of traffic and my toddler was in the backseat so I can’t remember exactly what was happening on my dash. I would turn the car on and off but I could not get it back into drive as the engine would not restart, but all of the electronics were still working. Finally someone offered to jump the car with one of those portable battery jumpers and that worked. I drove straight to autozone to see if it was something their machines would pick up on but they couldn’t find anything wrong. The dealer also couldn’t find anything wrong. I believe this is related to the auto idle stop feature.

On multiple occasions, after stopping the vehicle (for example at a red light), the engine would stop and not restart. After several minutes of frantically trying to restart the vehicle in dangerous situations (stopped in the middle of traffic and nearly rear ended multiple times), the vehicle would eventually start the engine. Bottom line - when stopping at a stop sign or red light, the vehicle turns off the engine and does not restart properly - placing all occupants in a dangerous situation.

The auto-idle engine system malfunctions constantly. For example, several times I almost got into dangerous or possibly fatal accidents- I was in stop and go traffic on an interstate. Traffic slowed to a stop. I held the brake. The engine idled. I took my foot off the break and moved it to the gas when the traffic abruptly restarted. The car stalled and shut down. The cars around me expected me to go and had to swerve around me while I desperately tried to restart. There is no way to set a default that the auto idle feature is off when I start the car. I have to remember to turn it off. This also happened at an on ramp with a stop light, I almost got rammed by the car behind me. This feature is a drain on the engine and battery and is dangerous when it is not working correctly. The default should be off or just not have it at all. Honda dealerships aren’t willing to help me.

Auto idle stop (ais) system. Had many of the other same symptoms that people reported. Our car would go into idle mode and then it would not restart. I would have to turn the car off I tried to do various things just to get it started again. This happened one time was the exited the highway and also happened coming out of a car wash location. I took it to Honda and they said because of the idle stop functionality the starter went bad and they had to replace that. I was compensated some money from Honda but I believe I was only done so because they knew something was wrong and I really believe there should be a recall for this. It is completely unsafe and very scary when it happens especially in the middle of traffic. Our starter was replaced because of this issue on November 5th 2024, but the symptoms had been going on for that whole calendar year prior.

 I have a concerning noise from my car's engine that I’ve already brought in for diagnosis. Knocking/ticking/rattling noise on stand-still acceleration at relatively low speeds/under light load. Does not duplicate when revving in park, only under light load. Sound present with hvac on or off. Does not make noise when cold or after long trips. Honda seems to be aware of this issue and has remedied it through work involving the crankshaft bearings and possibly other components as it relates to their service bulletin 23-097. The problem is that my vehicle falls outside of the stated range of production years as mine is a 2020 model year, but the likelihood seems quite high that the engine in my vehicle is suffering from this exact problem. The service department refuses to help me and the corporate line I've contacted through email me simply refers me to the service department. I just spent $38,000 on this vehicle with 30,000 miles and I have no other recourse at this point to remedy this.

The auto idle feature cuts out the engine in stop and go traffic and will not restart. This has happened on numerous occasions, creating unsafe conditions for traffic.

Idle stop caused engine to stall 3 separate times leaving me stranded in busy intersections making it difficult to restart vehicle and move safely out of the way. Initial start up checks come on, asked to put car in park, step on brake to restart car, car won’t restart. Once happened at night and shut off all my lights for 30 seconds making me not visible for cars coming up to me.

While stopped in preparation to make a left turn across traffic on a 4 lane road, our 2020 Honda Odyssey engine stalled- the engine idle stop function did not restart the engine as designed. We had to restart our car, but the car did not immediately restart, it took us 2-3 attempts. There was no prior warning or indication there was a problem. We could have easily been hit by another car, injuring my wife and children. Our system is available for inspection, we have not had it inspected yet.

Vehicle driver side sliding door has issues closing. Mentioned to dealer, but dealer dismisses it as possibly from water residue after car washes. Door needs to be manually closed with pressure to latch. Vehicle has lost all electrical function while in economy mode while in idle mode while at red lights and also while parked with accessories running. Vehicle batter life was verified and in excellent condition at battery replacement shop.

At a stop light the engine idle shutoff feature shut off the engine. Then a few moments later the entire vehicle shut off. I could not turn the vehicle back on after trying several times to do so. After about five attempts the vehicle turned back on in park gear. During this time the light turned green and the vehicle would not turn on, cars behind began honking. This has happened a few times since owning the vehicle. I was dead in the middle of a busy intersection. I have asked the dealer to look at the electrical system as there have been several anomalies but it checks out fine. I replaced the battery thinking that might be the problem but did not work. I believe it is the same problem as pe22005.

When the car engages the idle stop feature and shuts the engine off, the engine does not restart immediately once the brake is released. This has happened multiple times but the last time a message appeared that said to change gears and restart the car. In the meantime the vehicle was in traffic and stopped for over a minute before it could be restarted. This put us in danger of a rear end collision as other cars were wanting to go.

On at least 5 occasions the car has not restarted after going into auto idle while stopped. Normally after pressing the brake pedal all the way down while stopped, the engine will shut off and then restart after releasing pressure from the brake pedal. When it doesn't restart, all the lights on the dashboard come on and you can't do anything. It won't restart if your press the start button and you can't shift it to neutral to push it out of the road. Eventually it will restart by pressing the start button. I have not had this problem if I turn off the auto idle, however you have to manually turn off the auto idle every time you restart the car.