Owner Notification Letter - The driven pulley in the transmission (CVT) was not properly hardened due to improper heat treatment during the manufacturing process. Over time, this may lead to abnormal wear to the driven pulley or damage to the CVT belt which may cause the vehicle to experience a slip accompanied by an abnormal noise and multiple warning lights illuminating. This may lead to not being able to move forward after coming to a stop.
full bulletin at NHTSA ↗2021 Honda Accord powertrain problems
severe Owners of the 2021 Honda Accord have filed 11 NHTSA complaints about the powertrain at roughly $2,500 to repair (U.S. federal records, as of August 2026). Source: NHTSA Office of Defects Investigation. See powertrain across all vehicles →
Complaints
11
Recalls
0
Avg fix
$2,500
| Model year | powertrain complaints |
|---|---|
| 2017 Accord | 32 |
| 2018 Accord | 128 |
| 2019 Accord | 37 |
| 2020 Accord | 14 |
| 2021 Accord (this page) | 11 |
| 2022 Accord | 6 |
1crash
2injuries
Is there a fix? Manufacturer service bulletins
The manufacturer has issued service bulletins covering powertrain on this vehicle — documented repair instructions, service campaigns, or warranty extensions sent to dealers. A TSB isn't a recall (it's not a free safety remedy), but it's the manufacturer acknowledging the issue and how to fix it.
Owner Notification Letter - The driven pulley in the transmission (CVT) was not properly hardened due to improper heat treatment during the manufacturing process. Over time, this may lead to abnormal wear to the driven pulley or damage to the CVT belt which may cause the vehicle to experience a slip accompanied by an abnormal noise and multiple warning lights illuminating. This may lead to not being able to move forward after coming to a stop.
full bulletin at NHTSA ↗Service Bulletin - Due to an improper heat treatment during the manufacturing process, the driven pulley in the CVT was not properly hardened. Over time, this may lead to abnormal wear to the driven pulley or damage to the CVT belt which may cause the vehicle to experience a slip accompanied by an abnormal noise and multiple warning lights. Some vehicles may not move forward after coming to a stop.
full bulletin at NHTSA ↗Service Bulletin - Due to an improper heat treatment during the manufacturing process, the driven pulley in the CVT was not properly hardened. Over time, this may lead to abnormal wear to the driven pulley or damage to the CVT belt which may cause the vehicle to experience a slip accompanied by an abnormal noise and multiple warning lights. Some vehicles may not move forward after coming to a stop.
full bulletin at NHTSA ↗Dealer Message - Today, December 2, 2022, American Honda is announcing a product update for a total of 75 model year 2021 Accord and CR-V units to address incorrect CVT operation which may cause vehicle slippage, noise, and illumination of the MIL. Refer to your eResponsibility report or perform an iN VIN status inquiry to determine which units in your inventory are affected.
full bulletin at NHTSA ↗Source: NHTSA manufacturer communications. Bring the bulletin number to your dealer or shop.
The failure pattern owners describe
Ten owners describe powertrain failures in 2021 Accords that fall into distinct patterns. The most frequent complaint is premature head gasket failure causing sudden engine shutdown. Several owners report all dashboard lights illuminating simultaneously on the highway or while driving, followed by immediate loss of engine power. One owner at 81,000 miles experienced white smoke from the exhaust and cylinder 4 misfire; another had the failure occur at just over 4 months ownership with minimal miles. None of these owners received prior warning signs—the failures were sudden.
CVT transmission issues appear as either post-service failures (one case involved overfilled fluid following dealership service, requiring a $10,100+ replacement) or spontaneous loss of drivability with harsh noise and vibration.
One owner encountered flashing check engine lights and power loss on a rainy highway; a TSB exists for this condition but the manufacturer declined to repair it.
Brake and throttle control problems surface in one complaint—steering shake during braking at highway speeds and slow throttle response simulating power loss.
Dashboard warning light clusters appear intermittently or persistently in several cases, sometimes with no clear diagnosis from dealers. The safety concern is consistent: owners faced dangerous situations with complete loss of power or uncontrolled vehicle behavior, often on busy highways with passengers aboard.
Same Honda Accord powertrain reports on nearby years: 2018 · 2019 · 2020
Failure modes owners describe
Head gasket failure
Premature head gasket failure causing loss of engine power, dashboard warning lights, and vehicle shutdown. Multiple owners report sudden, unwarned failures occurring with no prior symptoms.
When: 81,000 miles (one case); others not specified; one at ~4 months ownership with low mileage
Symptoms owners cite: All dashboard lights illuminate simultaneously; Engine power loss on highway; White smoke from exhaust; Engine misfire (cylinder 4 reported in one case); No prior warning signs or check engine light in some cases
Codes mentioned: P0300 (misfire, general), Check engine light (blinking)
Repairs/costs cited: Honda dealer estimated $4,400 for repair; requires transmission or gasket replacement depending on damage extent
Recalls/TSBs owners mention: Honda aware of premature head gasket failures in 1.5L engines but has not issued recall or TSB per owner statement; dealer declined responsibility in some cases
CVT transmission failure
CVT transmission failure occurring shortly after dealer service or spontaneously, with internal damage and fluid overfill. One case involved overfilled transmission fluid post-service; another involved sudden loss of drivability with no prior transmission work.
When: Shortly after CVT service (one case); early in vehicle ownership (4 months, low mileage)
Symptoms owners cite: Abnormal noise and vibration; Harsh driving conditions; Loss of vehicle motion/inability to move; Loud thud followed by uncontrolled brake application
Codes mentioned: CVT control system faults (referenced by owner)
Repairs/costs cited: Transmission replacement estimated at $10,101.13; internal transmission damage identified at dealership inspection
Recalls/TSBs owners mention: CVT control information available per owner; dealership (Classic Honda of Midland) refused responsibility for post-service failure
Engine power loss and flashing check engine light
Sudden loss of engine power during highway driving with flashing check engine light, then spontaneous recovery. TSB exists for this issue but manufacturer declined repair.
When: During highway driving in heavy rain; no mileage stated
Symptoms owners cite: Engine power loss while passing; Flashing check engine light; Difficulty maintaining steady power state; Spontaneous recovery after stopping
Codes mentioned: Check engine (flashing)
Repairs/costs cited: None provided; dealer stated nothing could be done with light off
Recalls/TSBs owners mention: TSB exists for this condition; Honda manufacturer declined repair per dealer communication
Dashboard warning lights and electrical/powertrain faults
Intermittent or persistent dashboard warning lights indicating check engine and powertrain system faults. In some cases lights illuminate temporarily; in others, lights appear without clear diagnosis. One case involved all dashboard lights coming on while parked.
When: Intermittent over 2-3 months in one case; sudden in parking in another; sporadic in others
Symptoms owners cite: Check engine light (intermittent or persistent); All dashboard warning lights illuminated; No clear mechanical symptoms in some cases
Codes mentioned: Check engine light (powertrain system), Multiple unspecified warning lights
Repairs/costs cited: Mechanics attributed to computer issue; dealer unable to diagnose root cause in some cases
Brake and throttle control issues
Steering wheel shake during braking and slow throttle response simulating power loss. Described as car losing power on inclines and rolling backward at stops.
When: Noted at 60-65 mph on curves; general driving conditions
Symptoms owners cite: Steering wheel shake during braking at 60-65 mph on curves; Slow throttle response; Vehicle rolls backward at stops; Loss of power on small inclines
Repairs/costs cited: Dealer unable to identify root cause
Synthesized from 11 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 1 most recent
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…
Had powertrain trouble with your 2021 Honda Accord?
File a complaint with NHTSA → It's free, official, and how every report above got here — owner filings are the federal safety record this page is built on.
Common questions
How serious is the powertrain problem on the 2021 Honda Accord?
It's a meaningful issue. 11 complaints have been filed and the failure mode causes operational problems for owners. Repairs average $2,500.
At what mileage does the powertrain typically fail?
Mileage data is limited for this issue. Owners report failures across a wide range, suggesting cause is more about driving conditions and maintenance than mileage alone.
What does it cost to fix?
Independent shops typically charge around $2,500 for powertrain repairs on this vehicle. Dealer pricing tends to run 20-40% higher. The exact figure depends on the specific failure mode, parts availability, and your local labor rates. If you're outside factory warranty, an extended service contract often covers this category.
Are there any recalls related to powertrain?
No active recalls currently cover powertrain issues on this vehicle. The complaints filed represent owner-reported failures that haven't risen to the level of a manufacturer-issued recall — but they're still worth knowing about before you buy or budget for repairs.
Related
Complaint and recall data sourced from the National Highway Traffic Safety Administration (NHTSA)
public records database. Verify the raw federal record at
nhtsa.gov/vehicle/2021/Honda/Accord.
Severity ratings are derived from reported crashes, fires, injuries, and fatalities. Repair cost estimates are
independent-shop national averages and may differ in your area. Some links on this page are affiliate links.