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.
2020 Honda Odyssey engine problems
73 complaints (15% of all complaints for this car). Typical mileage when it fails: 51,000. 1 crash reported.
- owner complaints
- 73
- of this car's complaints
- 15%
- typical mileage
- 51,000
- crashes
- 1
- recalls
- 0
Which part fails
Owners did not name a specific part.
At what mileage
Complaints by mileage at the time of the problem.
Honda Odyssey engine problems in other years
Specific symptoms reported on the 2020 Honda Odyssey engine
Phrases found in the owners' own descriptions, so one complaint can mention several symptoms.
Stalling 26Won't start 11Knocking 10Loss of power 9Check engine light 8Engine failure 8Overheating 6
Related recalls
No recalls on record for this model year.
Related investigations
Engine failure
The Office of Defects Investigation (ODI) has received 414 reports of connecting rod bearing failures in the 3.5L V6 engine used in the following vehicles: Model Years (MY) 2018-2020 Acura TLX, MY2016-2020 Acura MDX, MY2016-2020 Honda Pilot, MY2018-2020 Honda Odyssey, and MY2017-2019 Honda Ridgeline. The subject engine failures were analyzed as part of a Recall Query (RQ24013). It was determined that these engine failures are outside the scope of Honda Recall 23V‑751. Further, evidence gathered in conjunction with RQ24013 does not suggest this failure is caused by the same crankshaft manufacturing defect that is addressed by Honda in Recall 23V‑751. Based on analysis of data from RQ24013, the federal safety agency has closed that investigation. The significant number of reports of engine failure in vehicles outside the scope of RQ24013 presents a potential safety risk that warrants further investigation. ODI is opening this Preliminary Evaluation (PE) to further evaluate the scope and severity of the potential problem and to fully assess the potential safety-related issues. To review the ODI reports cited in the Opening Resume ODI Report Identification Number document, go to
PE25008
No Restart After Auto Start/Stop Engages
On June 3, 2022, the Office of Defects Investigation (ODI) opened Preliminary Evaluation PE22005 after the agency received VOQs and several field reports concerning the Auto Idle Stop (AIS) feature on 2016-2019MY Honda Pilot vehicles. The complaints allege that the engine fails to restart on its own from a complete stop at a traffic light or road intersection with the AIS function engaged. The subject vehicles are equipped with a 3.5L engine with a 9-speed automatic transmission. On January 6, 2023, Honda released service bulletins 23-008 and 23-009. These service bulletins address the failure to restart issue in the 2016-2019MY Honda Pilot vehicles, as well as the 2015-2020 Acura TLX, 2016-2020 Acura MDX, 2019-2022 Honda Passport, and 2020-2023 Honda Ridgeline vehicles. The repair outlined in the service bulletins is a two-stage countermeasure to remedy the issue. The first stage is a Programmed Fuel Injection (“PGM-FI”) software update. The second stage is only deployed if the software update fails to remedy the issue. The second stage, depending on the model and model year, consists of replacement of the starter assembly, starter relays, and a valve adjustment. Additionally, Honda extended the warranty coverage to 10 years with unlimited mileage for vehicles requiring the second stage component replacement. ODI continues to receive complaints of the AIS failure to restart, with many complainants alleging the campaign countermeasures had been completed.the federal safety agency has reviewed Honda's Information Request Letter responses involving warranty claims, lawsuits, and consumer complaints in addition to ODI's own data. This Engineering Analysis is being opened to further consider the potential safety defect, including gathering additional data regarding Honda’s service campaign efficacy. ODI is additionally expanding the scope to encompass all vehicles addressed in Honda’s service bulletins 23-008 and 23-009 as well as newer model year vehicles, which are substantially similar to the vehicles covered by the service campaign. To review the ODI reports cited in the Opening Resume ODI Report Identification Number document, go to
EA25004
Engine failure
On November 8, 2024, the Office of Defects Investigation (ODI) opened Recall Query RQ24013 to assess the scope of Honda recall 23V‑751 after receiving complaints that alleged connecting rod bearing failures in vehicles that were not within the scope of recall 23V‑751. In November 2023, Honda recalled 248,999 various Model Year (MY)2016â2020 Honda and Acura vehicles equipped with the 3.5L V6 engine. Honda recalled these vehicles due to a crankshaft manufacturing defect that caused premature connecting rod bearing wear and engine seizure. While the out-of-scope failures involved in these complaints appear to have a very similar failure mechanism as the recalled engines, a thorough analysis of all available data from Honda has not indicated that the same manufacturing defect exists in the out-of-scope engines as the engines recalled by 23V‑751. Based on this analysis ODI has determined that Honda has properly defined the scope of recall 23V‑751. Consequently, ODI will close this RQ investigation. the federal safety agency will continue to investigate these complaints of engine failure as part of a new Preliminary Evaluation Investigation (PE25008). The Agency reserves the right to take additional action if warranted by new circumstances.
RQ24013
What 2020 Honda Odyssey owners say
Most recent owner complaints, unedited.
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.
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.
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 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.
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.
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:Â [XXX] Mileage at time of failure:Â 155413 Component: Engine â 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 the federal safety agency'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.
Questions about the 2020 Honda Odyssey engine
Does the 2020 Honda Odyssey have engine problems?
Owners have filed 73 complaints about the engine of the 2020 Honda Odyssey, 15% of all its complaints.
At what mileage do 2020 Honda Odyssey engine problems start?
The typical (median) mileage in owner complaints is 51,000 miles.
Was there a recall on the 2020 Honda Odyssey engine?
There is no recall for this problem on this model year.
What year does the Honda Odyssey have bad engine?
The Honda Odyssey model years with the most engine complaints are 2025 (263 complaints), 2018 (205 complaints) and 2005 (155 complaints).
Other 2020 Honda Odyssey problems
Driver assistance 218Electrical 175Body 32Fuel system 32Brakes 22Airbags 20Transmission 17Acceleration 14Suspension 10Visibility 10Lights 4Seat belts 4Steering 4Locks 3Seats 3
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