I would like to report a known issue with the Honda Accord Sport 1.5t. My head gasket went out Aug. 2024 with about 100,000 miles on the dashboard. The cost to change it was about 4100. My Turbo Charger is now out Dec. 2025, and they are quoting me about 2100 before taxes. The dealership did advise that there is a known issue with the head gasket going out prematurely due to a default with the…
2020 Honda Accord engine problems
moderate 38 complaints filed with NHTSA · avg repair $3,100 · see engine across all vehicles →
Failure mileage
Complaints
38
Recalls
0
Avg fix
$3,100
What stands out
Owners have filed 38 engine complaints with NHTSA against this vehicle, but no formal recall covers the issue — the federal record reflects what manufacturers have admitted, not everything owners are reporting.
The failure pattern owners describe
Buyer takeaway: A 2020 Accord with the 1.5L turbo engine carries documented risk of premature head gasket failure (starting around 73,000 miles) leading to sudden power loss on the highway, followed by turbocharger failure and costly repairs ($4,100+ for head gasket, $2,100+ for turbo). No recall exists despite widespread owner reports and dealer acknowledgment of the issue as recurring.
The 2020 Honda Accord engine cluster shows a pattern of catastrophic failures concentrated in the 1.5L turbo model. Head gasket failure is the dominant complaint, with owners across multiple complaints reporting sudden loss of power on highways between 73,000 and 113,000 miles. Coolant leaks into cylinders, triggering misfires, limp mode, and complete stalling without prior warning. Dealership service advisors have confirmed to owners this is a known recurring issue specific to the 1.5L turbo engine—one advisor stated they'd already seen multiple cases in one week.
Turbocharger failure follows head gasket failure in a cascade: dealers tell owners the turbo typically fails after head gasket replacement. Several owners cite diagnostic code P0299 (underboost), indicating the turbo cannot maintain boost pressure.
Secondary engine problems include rough idle and vibration, misfire codes, valve cover warping causing severe oil leaks, engine running rich with fuel in the oil, and driveshaft fracture at 39,000 miles. One owner reported loss of power at just 300 miles.
Multiple owners describe unsafe highway situations with sudden deceleration in traffic, and one owner noted being nearly struck by passing vehicles when power dropped unexpectedly. Dealers have cleared fault codes without diagnosing root causes. No manufacturer recall has been issued, though online forums and class-action discussions indicate thousands of affected owners. Repair costs exceed $4,100 for head gasket alone, not including turbocharger replacement.
Same Honda Accord engine reports on nearby years: 2017 · 2018 · 2019 · 2021 · 2022
Failure modes owners describe
Turbocharger failure / underboost
Turbocharger loses boost pressure or fails completely, often preceded by head gasket failure. Owners report sudden power loss, inability to accelerate safely, and diagnostic code P0299 (turbocharger underboost). Multiple owners cite dealers confirming this is a recurring issue on 1.5L turbo engines.
When: Between 73,000 and 113,000 miles; some as early as first occurrence noted at 111,000 miles
Symptoms owners cite: Sudden loss of engine power during acceleration and highway merging; Vehicle unable to accelerate; limited to 15 MPH or less in some cases; Check engine light illuminates; Vehicle enters limp mode; No warning before failure in most cases
Codes mentioned: P0299 (Turbocharger Underboost)
Repairs/costs cited: Turbocharger replacement quoted at $2,100 before taxes; often occurs after head gasket repair
Head gasket failure
Head gasket fails prematurely, allowing coolant to leak into the cylinder. Owners report dealers confirming this is a known issue specific to 1.5L turbo engines. One dealer service advisor stated the issue was so common they had seen multiple cases in one week.
When: As early as 73,000 miles; reported at 100,000, 108,000, and 113,000 miles in submitted complaints
Symptoms owners cite: Sudden loss of motive power while driving; Engine stalls without warning; Check engine light and multiple dashboard warning lights illuminate simultaneously; Vehicle enters limp mode; Rough idling and vibration; Abnormal fuel odor in oil; Engine overheating; Inability to start or repeated failed start attempts; No warning light before failure occurs
Codes mentioned: P0300 (Random misfire), P0304 (Cylinder 4 misfire)
Repairs/costs cited: Replacement cost $4,100 at one dealership; repair was not completed in some cases due to customer refusal or lack of confidence in dealership diagnosis
Recalls/TSBs owners mention: Dealer confirmed to one owner that head gasket failure is a known issue with the 1.5L turbo engine; no recall issued despite multiple owner complaints and online reports
Valve cover gasket / plastic cover warping
Plastic valve cover warps, failing to seal properly and causing severe oil leaks from the valve cover. One owner who is an ASE-certified master mechanic discovered the plastic cover was extremely warped; the dealership service advisor stated they had already seen this issue twice in one week on other vehicles.
When: Early in ownership; discovered at time of first oil leak repair
Symptoms owners cite: Massive oil leak from valve cover; Oil covers entire engine bay; Burning smell from oil on hot engine components; Fire risk due to oil on exhaust; Leak recurs after initial repair despite gasket replacement
Repairs/costs cited: Plastic valve cover assembly replacement cost owner $150 out-of-pocket after dealership failed to identify warped cover on first attempt
Misfire / ignition system issues
Engine misfires on specific cylinders, often causing rough running, vibration, and limp mode. Some owners replaced ignition coils and spark plugs multiple times without resolving the issue; root cause often identified as failed head gasket allowing coolant into cylinders.
When: Varies from 13,762 miles to 113,000 miles
Symptoms owners cite: Check engine light illuminates; Rough idle and vibration; Vehicle enters limp mode; Jerking and hesitation during acceleration; Cylinders 1, 2, or 4 reported wet; Engine sputtering and vibration as if about to stall
Codes mentioned: P0300 (Random misfire history), P0304 (Cylinder 4 misfire)
Repairs/costs cited: Multiple owners replaced ignition coils and spark plugs without resolving issue; underlying head gasket failure was the actual cause
Engine running rich / fuel system issues
Engine runs rich with fuel, triggering check engine lights and multiple ADAS warning lights. Owners report fuel in oil, gasoline smell in oil, and ADAS system failures as secondary symptoms. One owner had fuel injectors replaced; another had oxygen sensor replaced without success before fuel injector replacement resolved the issue.
When: Spring 2023 and other unspecified times
Symptoms owners cite: All ADAS warning lights illuminate simultaneously; Check engine light illuminates; Fuel odor in oil; ADAS system components stop working (collision mitigation, adaptive cruise, hill start assist); Rough engine running
Codes mentioned: System too rich (Bank 1)
Repairs/costs cited: One owner replaced oxygen sensor without success, then four fuel injectors which resolved the issue; another owner had dealership replace ignition coils and spark plugs after fuel-rich code
Driveshaft fracture
Driveshaft fractures with no prior warning, rendering vehicle undrivable. Occurred at relatively low mileage.
When: 39,000 miles
Symptoms owners cite: Abnormal noise from driveshaft area; No warning light illuminated; Driveshaft fractures, vehicle becomes non-drivable
Repairs/costs cited: Driveshaft replacement required
Engine power loss in limp mode / loss of motive power
Vehicle suddenly loses power and enters limp mode, typically triggered by sensor issues or fault codes. Owners describe unsafe situations on highways with sudden deceleration. In some cases, power returns after restart; in others, vehicle is immobilized.
When: Varies from very low mileage to higher mileage; one case at 300 miles
Symptoms owners cite: Sudden loss of motive power while driving at highway speeds; Vehicle enters limp mode, speed limited to 15 MPH or stalls completely; Check engine light illuminates; Multiple dashboard warning lights illuminate; Vehicle may restart and operate normally, or remain non-functional; Occurs without warning while driving in rain or normal conditions
Codes mentioned: P0300 history code
Repairs/costs cited: Codes cleared at dealer in some cases with no repair; underlying cause often identified as head gasket or sensor issues
Recalls/TSBs owners mention: One dealer suggested wet sensor caused limp mode; no repair performed
Unintended deceleration and brake assist malfunction
Vehicle decelerates without driver input, and brake assist system activates independently causing sudden braking. Safety-critical issue occurring at low speeds.
When: Unspecified
Symptoms owners cite: Inadvertent deceleration at 40 MPH without warning; Brake assist activates independently; Sudden unexpected braking; Multiple warning lights illuminate
Repairs/costs cited: Vehicle not repaired; no diagnostic testing completed
AC / refrigerant leak
Air conditioning system leaks refrigerant from condenser and discharge hose, failing to cool within short mileage. One owner reported leak at only 6,623 miles.
When: 6,623 miles
Symptoms owners cite: AC not cooling despite being set to 'LO'; Warm air blows from vents instead of cold air; Refrigerant leak from condenser and discharge hose
Repairs/costs cited: Repair cost quoted at $10,066.62 plus tax for owner with only 6,623 miles
Synthesized from 38 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 4 most recent
Driving on the freeway and the car started to lose power and de-cellerate, eventually stopping. After leaving it overnight, I returned and the car started. I slowly drove it to a dealership within 3 miles. The dealer said they could not replicate the issue. They did find a "labor diag found in history code p0304" .
Nothing happened, I just want to know if my engine is a 1.5 or 2.0
I had just left my job in Albany and was headed to the Latham area, while merging into traffic on I-90 West my 2020 Honda Accord EX-L started to rattle and slow down, numerous lights illuminated simultaneously on my dashboard. I immediately pulled off the north shoulder and restarted my vehicle to no avail, the dashboard lights were still lit and my vehicles speed and steering were compromised.…
Had engine trouble with your 2020 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 engine problem on the 2020 Honda Accord?
It's a documented issue but not catastrophic. 38 complaints have been filed. Repairs average $3,100 and most owners catch it before it causes a breakdown.
At what mileage does the engine typically fail?
Across the 8 complaints that reported odometer mileage, most engine failures cluster between 13,762 and 100,000 miles, with the median around 62,000. A quarter of owners report trouble before 13,762; a quarter make it past 100,000. Maintenance history matters more than the odometer alone — this is the reported failure window, not a guarantee.
What does it cost to fix?
Independent shops typically charge around $3,100 for engine 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 engine?
No active recalls currently cover engine 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/2020/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.