Mileage when the problem started
Owner reports
Selected complaints filed with NHTSA by 2021 Honda Accord owners, lightly cleaned up (personal details are redacted by NHTSA).
The contact owns a 2021 Honda Accord. The contact stated that while her son was driving 55 MPH, the vehicle shut off with several warning lights illuminated on the instrument panel. The contact's son pulled off to the shoulder of the highway and had the vehicle towed to a dealer. While at the dealer, the mechanic discovered coolant leaking into cylinder #2, causing an engine misfire. The dealer replaced the head gasket. After the repair, the failure returned immediately upon driving the vehicle home from the dealer. The vehicle was taken back to the dealer and the failure persisted upon return of the vehicle. While checking the repair order, the contact discovered that the service report was blank. The dealer was unable to duplicate the failure or determine the cause of the issue. The contact was not notified of the issue after retrieving the vehicle. …
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. …
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.
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.
The contact owns a 2021 Honda Accord. The contact stated that while driving approximately 30 MPH, the message "Emission System Problem" was displayed. The vehicle was taken to the dealer, where it was diagnosed and determined that the turbocharger had failed and needed to be replaced. The contact was informed that the failure was a common issue. The vehicle was repaired. The manufacturer was not notified of the failure. The failure mileage was approximately 108,579.
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,
NOTE: the item / malfunction described below is CURRENTLY UNDER RECALL for multiple Honda models but has not YET been recalled for the 2021 Accord Sport 2.0T. Please add this model to the recall list!!! I had been driving on the interstate for about 30 minutes on Thursday, 11/7, when suddenly seven of the warning lights flashed in succession on my vehicle, including braking system warnings, emission system warnings, and tire pressure system warmings. I pulled to the side of the road, quite concerned. I called the dealership. The service professional thought it might be the radar on the front camera causing an electrical system malfunction. I was advised by the service technician to drive slowly (about 55mph) and come to the dealership (about an hour away). Upon inspection by the dealer, it was determined that the high-pressure fuel pump in the engine was defective. …
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 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. …
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. …
Engine complaints in other Accord years
Frequently asked questions
How common are engine problems on the 2021 Honda Accord?
NHTSA has 41 complaints about the engine & cooling of the 2021 Honda Accord, 17% of the model year's 245 complaints.
Is there a recall for 2021 Honda Accord engine problems?
No. NHTSA lists no engine & cooling recall for the 2021 Honda Accord, though it has 4 recalls for other components. If the problem is widespread, a repair may still be covered by an extended warranty or a manufacturer service bulletin — ask a dealer.
At what mileage do 2021 Honda Accord engine problems start?
Half of the complaints with a recorded mileage happened before about 109,000 miles.
Is it dangerous?
Owners linked 3 crashes, 0 fires and 2 injuries to engine & cooling problems on this model year. If you notice symptoms, have the car checked before driving further.
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.