2021 Honda Accord Engine Problems

I own a 2021 Honda Accord Hybrid. Shortly after purchasing the vehicle as a used vehicle in 2023, I began experiencing intermittent air conditioning performance. The A/C would gradually lose cooling capacity over time until it was no longer able to cool the cabin effectively. To temporarily restore operation, I added refrigerant approximately twice per year, believing the system had developed a minor leak. As the condition worsened, I brought the vehicle to an authorized Honda dealership for diagnosis. The dealer diagnosed the vehicle with a leaking A/C condenser and a leaking heat exchanger pipe and recommended replacement of both components. Honda declined goodwill assistance because the vehicle is outside the original warranty period. I later learned that Honda previously issued an extended warranty for A/C condenser failures on 2018–2020 Accord models due to a known condenser defect. My vehicle exhibits the same symptoms of gradual refrigerant loss and declining cooling performance, despite being a 2021 model year. In researching this issue, I found multiple reports from other 2021 Accord and 2021 Accord Hybrid owners describing similar A/C condenser failures and refrigerant leaks. I am submitting this complaint because I believe there may be a broader pattern affecting 2021 Accord vehicles that warrants review. I am requesting that NHTSA document this complaint and evaluate whether similar failures are occurring in 2021 Honda Accord and Accord Hybrid vehicles.

NHTSA ID

11752456

Incident

Jul 23, 2026

First of all started with small coolant missing, later on I started noticing power loss and finally white smoke out the exhaust. Blown Head Gasket. Honda need to own up on defect engine design the ford did awhile back. Those slits between the cylinder was a big mistake. I myself is doing the repair. 2021 Honda Accord Sport 2.0 with mods and tuned

NHTSA ID

11749905

Incident

Nov 28, 2025

I am submitting this complaint regarding my 2021 Honda Accord because of a serious safety issue involving the turbocharger and fuel injector system. While driving on the highway, my vehicle experienced a failure related to the turbocharger and fuel injector system, which caused multiple warning sensors to activate and resulted in the vehicle suddenly losing power and becoming unable to continue driving. This unexpected failure forced my car to stop in the middle of the highway, placing me and other motorists at significant risk of a serious accident or fatality. A vehicle should not suddenly become inoperable while traveling at highway speeds due to a mechanical defect. This creates an extremely dangerous situation, especially in heavy traffic where other drivers may not have sufficient time to react. After researching this issue, I discovered that numerous other owners of 2021 Honda Accords have reported similar failures involving the fuel injectors and turbocharger. Given the number of reported incidents and the serious safety risks associated with these failures, I believe this represents a potential defect that warrants investigation. I respectfully request that the National Highway Traffic Safety Administration investigate this issue and require Honda to issue a safety recall if appropriate. No driver should have to experience a sudden loss of power that leaves them stranded in moving traffic due to an apparent vehicle defect.

NHTSA ID

11749412

Incident

Jul 1, 2026

The vehicle suffered an unexpected loss of engine compression and dropped into a dangerous Limp Mode while driving due to a Cylinder 3 Misfire code (P0303). The manufacturer dealership misdiagnosed the mechanical issue using an unrelated 2.0L engine service bulletin (SB23-026) to clear the error. Six months later, the dashboard completely illuminated again with code P0299 (Turbocharger Underboost) caused by progressive pressure and compression loss across the 1.5L turbo engineering components. Upon post-visit inspection, engine fluids were found severely depleted. This ongoing engineering failure causes a sudden loss of vehicle motive power on public highways, creating a severe, recurring safety hazard that mirrors the active federal engine defect class-action litigation against American Honda Motor Co. This has happened 4 times with all the lights on my dash coming on Dec 2025, May 2026, June 2026 (2x)

NHTSA ID

11745437

Incident

Dec 2, 2025

The contact owns a 2021 Honda Accord. The contact stated that while driving at an undisclosed speed, the vehicle decelerated and was hesitating while accelerating. The vehicle was taken to the dealer, where the spark plugs were replaced. The contact stated that months later, the vehicle experienced the same issue and was taken back to the dealer, where it was diagnosed with a blown head gasket. Two months later, the spark plugs were replaced again. Another two months later, additional components were repaired. The vehicle had been at the dealer for several months and the technicians were unable to determine the cause of the failure. The low engine oil warning light was illuminated, even though the engine oil level was not low. The dealer was unaware of the cause of the failure and stated that the engine needed to be dissembled for further inspection. The vehicle was not repaired. The manufacturer was notified of the failure. The failure mileage was 133,000.

NHTSA ID

11745014

Incident

Dec 1, 2025

Mileage

133,000 mi

I am filing a complaint regarding the premature head gasket failure on my 2021 Honda Accord, which failed on May 28, 2026, with only 89,000 miles on the vehicle. A head gasket is a critical engine component that should last well beyond 89,000 miles under normal driving conditions and proper maintenance. I purchased this vehicle because of Honda's reputation for reliability and longevity, and I am extremely disappointed to experience such a major engine failure at this mileage. After researching the issue, I found numerous reports from other Honda Accord owners experiencing similar head gasket failures, particularly in newer models equipped with the 1.5L turbocharged engine. Many owners report engine misfires, coolant loss, overheating, and costly repairs at relatively low mileage. This suggests there may be a broader issue affecting these vehicles rather than normal wear and tear. My vehicle has been properly maintained, and I did not expect to face a repair of this magnitude before reaching 100,000 miles. The cost of replacing a failed head gasket is substantial and places an unfair financial burden on owners who reasonably expect Honda vehicles to provide dependable service. I respectfully request that Honda review this matter, investigate the growing number of similar complaints, and provide assistance with repair costs. I believe Honda should stand behind its products and support customers who experience premature component failures. Thank you for your attention to this complaint. I look forward to a prompt response and a fair resolution.

NHTSA ID

11741975

Incident

May 28, 2026

2021 Honda Accord EX-L, 1.5T turbocharged engine. Within 8 months of purchase at approximately 21,900 miles, I experienced three separate incidents of sudden complete engine power loss at highway speeds. During each incident the vehicle would not exceed 2,000 RPM and multiple warning lights illuminated simultaneously including check engine, TPMS, brake system warning, and Honda Sensing alerts. The vehicle was inspected by two independent Honda dealerships on multiple occasions including cylinder drop tests, leakdown tests, and full fluid checks. The vehicle passed every test at both locations with fluids confirmed properly maintained. Despite passing all professional inspections the power loss incidents continued to recur. The third incident occurred in a residential driveway with a passenger present and was captured on video. A Honda dealership subsequently diagnosed a head gasket coolant leak with an estimated repair cost of approximately $8,000. Research revealed numerous other 2021 Honda Accord 1.5T owners reporting identical symptoms regardless of maintenance history. This appears to be a known design defect in the 1.5T cylinder head where a narrow coolant passage represents a structural weak point that fails regardless of maintenance. Owners have been reporting this to NHTSA since 2024 requesting a recall. This defect created dangerous conditions at highway speeds with passengers present on multiple occasions. The vehicle is currently available for inspection at a Honda dealership. I am requesting NHTSA investigate and initiate a formal recall of all affected vehicles. i have everthing documeneted from the 4 dealship visit ive done since the start of the issue.

NHTSA ID

11735578

Incident

Mar 26, 2026

The lights and warnings below popped up on my dash after the engine light had come on and then off again for about a week. See below, -Emission system problem Avoid heavy acceleration and high speed. See dealer -tpms light -brake system problem -brake hold system problem -electric power steering system problem -vehicle stability assist system problem -hill start assist problem -adaptive cruise control system problem -collision mitigation braking system problem -road departure mitigation system problem Went to get diagnosed at the dealership and was told that the turbo on my engine had failed. Mechanic said it had nothing to do with me and that it failed on its own. I saw that it was a reoccurring problem with other Honda owners with the same year, make, and model as mine but are being given the run around and no solution.

NHTSA ID

11731289

Incident

Mar 17, 2026

Head gasket issue please fix this problem for the customers

NHTSA ID

11729907

Incident

Apr 7, 2026

Driving on the highway, my dashboard lit up like a Christmas tree. Car started having white smoke at tail pipe. Check engine lit blink 5 times. Had 4 kids under 14 years old in car. Almost got hit trying to merge over. Turns out misfire cylinder 4. Head gasket. Only 81,000 miles. I have owed 5 months. Car currently at Honda, they want almost 4,400 to repair. But apparently, Honda is aware of these HEAD gaskets going prematurely, in 1.5 l. and has done nothing about it. I do not have the money to repair this car on top of how dangerous it was to be driving on the highway.When this happened.

NHTSA ID

11726618

Incident

Mar 21, 2026

I am writing to file a complaint on the service that was provided at Vann York Honda. On February 17, 2026, I was returning home from work and my car had a hard idle at start up. I was able to drive it home without issue. The next day, February 18, I got in my car and I had another hard idle start with many check engine codes appearing on the dashboard. I drove it to Vann York Honda in High Point, North Carolina for service. I was told it was a faulty fuel injector causing the problem and that it needed to be replaced. I left the car there over night and paid for the service; approximately $3,000. I got the car back on February 19. On February 20, I again had a rough idle on start up. I brought the car back to Vann York Honda and advised them that I was experiencing the same issue as before. The mechanic brought it to the back and advised me that he could not find anything wrong with the vehicle and that it is running fine. I expressed my concerns with the vehicle and he stated that without a error code or check engine light being on, it would be difficult to diagnose. The technician and the advisor said to keep driving it until a light comes on saying there is a problem since they could not find an issue. in the following 2 weeks, I had regular rough idles on start up and the fuel efficiency dropped approximately 6 miles per gallon. When I filled the car with gas, the fuel range dropped from 540 to 370. When I called about that issue, they said they reset the computer when performing the previous service on the vehicle and it is taking time for the computer to "learn" the car again. On March 6, I brought the vehicle back to Vann York Honda due to many check engine codes appearing on the dashboard. On the way to Vann York, the service advisor called me and stated that she would be reaching out to Honda Corporate to see about Honda paying for some of the cost of this service. My wife and I drove into the service bay and I spoke with the service adviso

NHTSA ID

11723808

Incident

Feb 18, 2026

I am reporting a serious safety concern involving my 2021 Honda Accord Sport SE. The issue began at approximately 78,000 miles when multiple warning lights suddenly appeared on the dashboard while driving. At the same time, the vehicle began shaking and had difficulty accelerating. The engine felt unstable and the car struggled to gain speed. I immediately took the vehicle to a mechanic where it was diagnosed with an engine misfire on cylinder 3. The spark plug and ignition coil were replaced. After this repair the vehicle appeared to run normally for a short time, but the exact same symptoms returned shortly afterward. The vehicle again began shaking while driving and experienced loss of power and poor acceleration. This creates a serious safety concern, especially when merging onto highways or driving in traffic where sudden loss of power could lead to an accident. After researching this issue, I discovered numerous complaints from other owners of 2021 Honda Accords describing the same symptoms that ultimately resulted in blown head gasket failures. These complaints appear in the NHTSA database and other consumer forums. The pattern of engine misfires, shaking, and loss of acceleration appears to be consistent across many vehicles with similar mileage. Despite the number of similar complaints, there are currently no recalls associated with my VIN. I believe this may indicate a broader manufacturing defect affecting these vehicles. I am requesting that NHTSA investigate this issue further to determine whether a safety defect exists that could require a recall or other corrective action.

NHTSA ID

11723127

Incident

Feb 12, 2026

All the lights came on in my car and it wouldn’t accelerate. Brought to dealership and they stated it was a blown head gasket and it was a known problem with the 1.5 turbo cars. There are also 2 others problems that are known problems with these cars and Honda isn’t doing anything about it.

NHTSA ID

11719498

Incident

Feb 17, 2026

Hello, I have a 2021 Honda Accord Sport 2.0T Engine. The engine has a 2.0 liter turbo. I have had to replace two fuel pumps, which were covered my extended warranty. Another issue that I had to repair, and one that has not fully been resolved is the head gasket. I have been losing coolant at an alarming rate. Every two weeks I have to fill up coolant. I had the head gasket repaired at a Honda Dealership, and this is currently being diagnosed by another Honda Dealership, as I do not want to deal with the Honda Dealership in Cedar Rapids, Iowa. Currently, a Honda Dealership in Iowa City, Iowa is handling the issue, but the head gasket along with the cylinder head were originally repaired in October 2025. Since December 2025, I have been losing coolant on a regular basis. I still have 5,000 miles left on my extended warranty, but there have been many owners who have had their head gasket replaced, or are needing replacement, and Honda refuses to acknowledge that there is a manufacturing defect with the engine. The 2.0 liter turbo engine has a major design flaw with it's cooling passages, and Honda has yet to come up with a resolution. Having an engine overheat is a major safety concern! The current dealership is driving my vehicle on a regular basis, in fact the service advisor is driving it to work and back home (35 miles each way) to replicate the problem. At this point, a recall should be issued by Honda, as there is currently a class action lawsuit that has occurred in the state of California.

NHTSA ID

11717122

Incident

Sep 4, 2025

Financed a used 2021 honda accord sport in April of 2024 with 68,671 miles. About a month ago, with no warning signs of any sort such as overheating etc...my car did not want to start, finally started but was sputtering with a rough idle, my dash lit up with like 7 or more warning lights. Including a flashing check engine light. All the were safety warnings from braking system not working, to power steering to emissions failure, etc... and to take to dealership. Got the car to a local mechanic to get a diagnostics reading and was told I had a misfire in cylinder 2. Replaced the #2 coil and spark plug. Thought everything was fine until picking up my daughter from school and then all those warning messages lit my dash up again including the flashing check engine light. Car started sputtering and went into limp mode. Lost power and by the grace of God was able t9 coast off the major Blvd away from traffic and out of harms way. Very, very scary. My life literally flashed before my eyes. Not only my life was in danger but my daughters along with other drivers around me. So I took it back to mechanic and he ran diagnostics again still had a misfire. He could not pin point the exact problem. Took it to the dealership and they confirm it was a faulty head gasket between CYL 2 and water jacket. And they quoted me a price of $5,998. Which i can not afford. And feel Im not responsible for catastrophic major mechanical failure. I maintenance my car regularly thru the dealership so they have record of me properly maintenancing the car. Head gasket failure at 80,000 miles is absolutely unheard of. Until I started researching and come to find out this is a design flaw made by Honda. I was flabbergasted with the amount of people with the exact type of problem. Im afraid that even after repairing this problem that it may happen again down the line. And that would be putting my life in danger. Vehicle is still at dealership being that I can not afford the repairs.

NHTSA ID

11716060

Incident

Jan 16, 2026

Starts Vehicle at cold start and notice right away engine turbulence, engine light flashing, lost some coolant and white smoke. Scan vehicle for codes, engine misfire #2.

NHTSA ID

11715440

Incident

Nov 17, 2025

Head gasket blew randomly. Just hit 100,000 miles. I was on the highway and my speed just started to decrease 65 to 35

NHTSA ID

11714521

Incident

Jan 29, 2026

Stretch timing chain 1.5 T, 86000 miles. It is very common in these motors. Just had to pay $2400 to have it replaced

NHTSA ID

11714285

Incident

Jan 16, 2026

The contact's girlfriend owns a 2021 Honda Accord. The contact stated that while his girlfriend was driving at an undisclosed speed, the check engine warning light and several other unknown warning lights illuminated. Additionally, the contact stated that the engine was slightly misfiring while driving. An independent mechanic replaced the spark plugs and the ignition coils at the residence; however, the failure recurred 3 weeks later. The mechanic inspected the vehicle but could not determine the cause of the failure. The vehicle was taken to the dealer, where it was diagnosed with head gasket and fuel injector failure. The contact was provided an estimate for the repair. The vehicle was not repaired due to the cost. The manufacturer was not notified of the failure. The failure mileage was approximately 74,000.

NHTSA ID

11705837

Incident

Nov 18, 2025

Mileage

74,000 mi

Vehicle accelerated on its own and propelled the vehicle over a curb and into a building. This occured even though the gear shift was in the Park position. My grandchild and I were thrown forward as vehicle hit the building. Vehicle has not been inspected since incident occurred just yesterday, 11/20/2025. No warnings preceded the incident,

NHTSA ID

11700745

Incident

Nov 20, 2025

The head gaskets are known to fail on the 10 generation accord. It failed on my 2021 Honda accord ex-l. I left work and while I was driving the dashboard lit up with every possible light. This was quickly followed by the vehicle losing power on the highway. I ultimately got it repaired by a Honda certified mechanic. The mechanic took it to a Honda dealer to confirm it was the gasket, in which it was. There were no warning lamps message or other symptoms prior to the failure. At the time of power loss I was on an 8 lane highway at 70mph. Luckily no accidents occurred, but the failure definitely put my safety at risk along with others. The mechanic I took my vehicle to has all available information if needed upon request.

NHTSA ID

11695539

Incident

Aug 27, 2025

I hereby state that my 2021 Honda Accord has experienced major mechanical failures involving the transmission and head gasket. The vehicle began exhibiting mechanical issues including rough shifting, loss of power, and engine overheating. Upon inspection by a qualified automotive technician, it was determined that both the transmission and head gasket have failed prematurely. These failures have rendered the vehicle unsafe and inoperable, resulting in significant repair costs, loss of use, and financial hardship. The nature and timing of these failures suggest a possible manufacturing or design defect. This statement is submitted in support of a formal claim and potential legal action against the responsible parties for the defective condition of the vehicle.

NHTSA ID

11694898

Incident

Oct 17, 2025

Car will drive fine , then all of a sudden it shuts completely OFF on the highway which is a MAJOR safety concern. ALL the lights will pop on in the dash board without any warning. Car will act as if it doesn’t want to pick up speed then after about 10-15 mins starts driving fine . This is my second time contacting you all regarding the same issues . Honda needs to definitely do a RECALL ASAP this is NOT SAFE at all to be driving around like this . ALOT of customers driving 2018-2022 Honda Accords have been having the same EXACT issues ..

NHTSA ID

11694363

Incident

Oct 17, 2025

Head Gasket Blown i had a diagnosis ran at the honda dealership and it came back as a blown gasket its Preventing me to accelerate whole on the highway im going at high speeds and it slows down like im slmming on brakes

NHTSA ID

11691826

Incident

Sep 18, 2025

This vehicles have a engineering flaw in the design of the head gasket failing prematurely disabling all components of vehicle at any given time wether it’s in the highway or local the car will basically shut itself down causing a major risk for the driver and civilians even death. This is a safety hazard, tragedy waiting to happen y’all should act now theirs multiple and quiet frankly the Corporation should be taking care of it since they are still allowing them out on the road even with knowledge of this issue the customer should not loose their life nor money to a mass production engineering flaw that’s is over seen by NHTSA, HONDA. I got in to an accident due to my vehicle not being at 100% because of the head gasket issue the cars availability to detect or use its components, mechanically or electrical.

NHTSA ID

11690197

Incident

Sep 13, 2024