2018 Honda Accord Hybrid

On February 21, 2022, the Office of Defects Investigation (ODI) opened Preliminary Evaluation (PE22003) to assess reports of inadvertent activation of the Collision Mitigation Braking System (CMBS), an automatic emergency braking (AEB) system, in model year 2017-2019 Honda CR-V and 2018-2019 Honda Accord vehicles.  The reports allege that activation of the AEB system occurs while driving with no apparent obstruction in the vehicle's forward path, resulting in sudden vehicle deceleration. Honda indicated that they were aware of a total of X,XXX reports that may relate to the alleged defect. Honda provided analysis of the alleged defect and alleges that some customers possibly had an inadequate understanding of the CMBS and its limitations.  However, many consumer complaints allege that Honda dealerships were unable to reproduce the condition or state that they were informed that this is considered normal CMBS operation. To date, ODI has received a total of 1,294 consumer complaints of inadvertent activation of CMBS in 2017-2022 Honda CR-V and 2018-2022 Honda Accord vehicles. A total of 31 complaints alleged a crash and 50 alleged an injury.  The Total column in the Failure Report Summary removes duplicate reports and shows the total number of reports with unique VINs from all Manufacturer, ODI, and EWR data sources.  In some cases, there were multiple reports associated with a particular vehicle in which recurring failures were alleged.  In total, there were X,XXX reports, 93 injury incidents and 47 crashes involving vehicles with unique VINs that may relate to the alleged defect. PE22-003 has been upgraded to an Engineering Analysis to further assess the scope, frequency, and potential safety related consequences of the inadvertent AEB activations. The scope has been expanded to include assessment of model year 2020-2022 Honda CR-V and Accord vehicles. To review the ODI reports cited in the Opening Resume ODI Report Identification Number document, go to NHTSA.gov.

NHTSA received a petition on or about July 18, 2022, requesting that Federal Motor Vehicle Safety Standard (FMVSS) 141 be applied to all electric and hybrid vehicles operating in the United States. The petition can be reviewed at NHTSA.gov under ODI Number 11486072. FMVSS 141 establishes performance requirements for pedestrian alert sounds for motor vehicles. The standard applies to hybrid and electric vehicles that have a gross vehicle weight rating of 4,536 KG or less or are defined as low-speed vehicles. The standard became fully applicable to all such vehicles manufactured on or after March 1, 2021.On January 27, 2023, NHTSA opened Defect Petition (DP) 22-005 to evaluate the subject matter described in the petition. On June 24, 2023 and as supplemented on June 25, 2023, the petitioner notified NHTSA he was withdrawing his petition. The petitioner indicated that, based on his review of data, there is no justification for asserting potential benefits that could be derived from actions sought by my petition. Based on the petitioner's withdrawal, DP22-005 is closed. Closure of this DP does not represent a determination by NHTSA regarding the subject matter of the petition.

On February 21, 2022, the Office of Defects Investigation (ODI) opened Preliminary Evaluation (PE22003) to assess reports of inadvertent activation of the Collision Mitigation Braking System (CMBS), an automatic emergency braking (AEB) system, in model year 2017-2019 Honda CR-V and 2018-2019 Honda Accord vehicles.  The reports allege that activation of the AEB system occurs while driving with no apparent obstruction in the vehicle's forward path, resulting in sudden vehicle deceleration. Honda indicated that they were aware of a total of X,XXX reports that may relate to the alleged defect. Honda provided analysis of the alleged defect and alleges that some customers possibly had an inadequate understanding of the CMBS and its limitations.  However, many consumer complaints allege that Honda dealerships were unable to reproduce the condition or state that they were informed that this is considered normal CMBS operation. To date, ODI has received a total of 1,081 consumer complaints of inadvertent activation of CMBS in the subject vehicles.  A total of 24 complaints alleged a crash and 42 alleged an injury.  The Total column in the Failure Report Summary removes duplicate reports and shows the total number of reports with unique VINs from all Manufacturer, ODI, and EWR data sources.  In some cases, there were multiple reports associated with a particular vehicle in which recurring failures were alleged.  In total, there were X,XXX reports, 84 injury incidents and 40 crashes involving vehicles with unique VINs that may relate to the alleged defect. PE22003 has been upgraded to an Engineering Analysis (EA24002) to further assess the scope, frequency, and potential safety related consequences of the inadvertent AEB activations.  Further the scope has been expanded to include assessment of model year 2020-2022 Honda CR-V and Accord vehicles. To review the ODI reports cited in the Opening Resume ODI Report Identification Number document, go to NHTSA.gov.

While driving on a bridge at under 20 mph, the vehicle's head gasket failed, causing the engine to overheat and coolant to leak from within the engine. The vehicle threw diagnostic trouble code P2601 and immediately entered "limp mode," severely cutting engine power and vehicle speed. Because this happened on a bridge with no shoulder to safely pull over, the sudden loss of power created a serious safety hazard — the vehicle could not maintain a safe speed or keep pace with surrounding traffic, increasing the risk of being struck by other vehicles. The vehicle was taken to a Tampa Honda (11000 N Florida Ave), where the failure was confirmed to be a blown head gasket that allowed coolant to leak into the engine cylinders. The head gasket and related components were replaced at a cost of approximately $5,000 to restore the vehicle to safe operating condition. The failed component is no longer available for inspection in its failed state, as replacement was required to make the vehicle drivable. No dealer, manufacturer representative, police officer, or insurance adjuster has inspected the vehicle; only at Tampa Honda facility that performed the repair diagnosed and confirmed the head gasket failure. Prior to this incident, no warning lamps or symptoms were noted — the P2601 code and limp mode activation occurred simultaneously with the sudden overheating and coolant loss, with no advance warning. This failure is consistent with a widely reported defect pattern among Honda vehicles with similar engines, where the head gasket fails prematurely and allows coolant to enter the cylinders. Honda has not issued a recall or acknowledged a manufacturing defect despite numerous consumer reports describing the same failure mode.

NHTSA ID

11761032

Incident

Aug 22, 2026

On 2-252026 my wife and I were driving on highway I-15 in California when the car started to accelerate, decelerate and jerk and the engine light came on. It was very scary because we were on a major highway driving around 60 MPH and cars were behind us when the deceleration happened. We could have been hit by cars traveling behind us or either we could have caused a major accident. We had to get off the highway and have the car towed to Honda for assessment. There was no engine light warning or service warning from Honda prior to this happening, it just randomly happened. The car was repaired at a Honda dealership and they said there was a leaking head gasket on cylinder number 4. When we looked up information regarding this head gasket failure we saw that other Honda cars have had the same problem and Honda is currently involved in lawsuits regarding this leaking head gasket on cylinder number 4.

NHTSA ID

11746562

Incident

Feb 25, 2026

While driving on the highway at approximately 65 mph with my child in the vehicle during rush-hour on May 21, 2026, my 2018 Honda Accord Hybrid Touring (105,746 miles) suddenly dropped speed, and began backfiring and stopped responding to the gas pedal. The check engine light flashed and the vehicle ran rough. I activated emergency flashers and drove slowly to the shoulder. Sunnyvale Honda (Sunnyvale, CA) diagnosed coolant intrusion into one of the cylinders and head gasket failure. The vehicle had never overheated and showed no prior warning signs. All maintenance was performed at Honda dealerships per the maintenance minder schedule. The dealership performed a head gasket repair costing $7,500+ out of pocket. On the first highway drive after pickup, again with my children in the vehicle, the identical failure occurred: backfiring, complete loss of throttle response, vehicle unable to exceed 48 mph with the accelerator fully depressed. The repair did not resolve the defect. The vehicle is currently back at the dealership for further investigation. This failure created an immediate safety hazard on both occasions: sudden loss of speed on highway with no warning. Honda Customer Service denied goodwill assistance. I am aware of numerous similar complaints involving coolant leak and head gasket failure on 2018-2022 Accord including complaints documenting the same failure on the Accord Hybrid 2.0L engine. NHTSA should investigate this as a potential safety-related defect affecting multiple Honda engine variants.

NHTSA ID

11746305

Incident

May 21, 2026

I am writing to file a formal complaint regarding my 2018 Honda Accord [VIN# [XXX] ] concerning what I believe to be a defective cylinder head or head gasket — an issue I have since learned is widely reported within the Honda owner community and is currently the subject of active class action litigation. Beginning at approximately 89,000 miles, my vehicle began experiencing episodes of engine rumbling followed by sudden shutoff. These episodes occurred two to three times before I brought the vehicle to an authorized Honda dealership at approximately 99,000–105,000 miles for diagnosis. At the dealership, I paid for a diagnostic inspection. I was informed that the technicians could not identify the root cause without performing a full engine pull and internal inspection, which they estimated would cost several thousand dollars — with an additional cost of $5,000–$8,000 if the diagnosis confirmed a cracked cylinder head or failed head gasket. Unable to absorb this expense, I did not authorize the repair. In an effort to keep the vehicle operational, I worked with independent mechanics and took the following corrective measures: replacement of spark plugs and ignition coils, replacement of the electric water pump, regular oil changes, maintenance of proper coolant levels, and avoidance of high or sudden acceleration. These measures allowed me to operate the vehicle for approximately one additional year without a recurrence of the shutoff events. Last summer, the vehicle failed to start entirely and could not be made operable. I was required to have it towed approximately 60 miles to its destination. The vehicle has not been operable since. Upon opening the hood, I observed coolant splashed across the engine cover consistent with a catastrophic head gasket failure. This failure occurred despite the vehicle being well maintained throughout my ownership. I believe this represents a known and systemic defect in Honda engine design for this model year. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOI

NHTSA ID

11740669

Incident

Aug 11, 2025

Over the past several years, there have been multiple instances where I or my wife are driving on the highway and the engine light comes on or starts flashing, and I am unable to go faster than 50 miles an hour, and the engine itself feels to be underpowered. We have taken it to the dealership for repair at least five times over the past five years and in each case they have attempted to do a repair and said the issue has been resolved, but the issue continue. At at least one of those visits, they have diagnosed the issue as an engine misfire issue. The issue has intensified from the initial symptoms, (which were as I described, but resolved by turning the car off, waiting 30 seconds to a minute and then turning the car on again) to how it is now: in addition to the check engine light, every other light and warning system has gone off when driving on the highway and the engine was unable to go faster than 40 miles an hour, and it does not resolve by restarting the car. The dealership and Honda America’s main phone line have as of yet been unable to give me a clear answer as to why this is happening or whether it can be fixed. A sudden drop in speed and power on the highway as we have experienced many times over the last five years is inherently extremely dangerous.

NHTSA ID

11715485

Incident

Jan 31, 2026

The car loses power. It starts as a misfire on cylinder 2 (P0302 code) and the engine starts to shutdown (or goes into a safe mode with no power). The result is loss of speed which creates a safety hazard especially on highways. This has happened multiple times and the car has been in the shop 4 times for this issue. We have to pull off the road, turn the car off, sit for a minute and restart the car. It will then run ok. This has happened during acceleration and when just trying to keep speed on an incline. The dealership has not been able to identify an issue. The head gasket was replaced in April 2025 because they thought there was a pin hole that was causing oil to push into the cylinder. The misfire continued to happen. It was in the shop on October 2025 and they found nothing wrong with the spark plug, induction coils, gas feed. Therefore no understanding of the root cause.

NHTSA ID

11693248

Incident

Oct 2, 2023

The contact owns a 2018 Honda Accord. The contact stated that upon starting the vehicle, various warning lights were illuminated. The contact stated that the Lane Departure, Lane Keep Assist, ACC, and Blind Spot Detection warning lights remained illuminated. The vehicle was taken to a local dealer, where it was diagnosed, and the contact was informed that the malfunction or warning lights were a result of the camera being faulty and that the camera needed to be replaced. The vehicle was not repaired. The manufacturer was notified of the failure. The approximate failure mileage was 105,000.

NHTSA ID

11686086

Incident

Sep 9, 2025

Mileage

105,000 mi

The engine head gasket failed due to design flows. I have to put coolants and oil on a daily basis to keep the car running to avoid overheating.

NHTSA ID

11683633

Incident

Aug 27, 2025

Dealer Message - On August 21st, 2026, American Honda issued a Product Update for certain 2018-2022 Accord and Accord Hybrid models that received the accessory Wireless CarPlay and Android Auto upgrade. Refer to Service Bulletin 26-068 for additional information regarding the Product Update.

Owner Notification Letter - Honda has developed software updates to the Honda Sensing system to enhance driver experience by modifying the circumstances when the advanced driver assist system (ADAS) decelerates the vehicle or the extent of deceleration. The software covers Adaptive Cruise Control (ACC), Collision Mitigation Braking System (CMBS), and Road Departure Mitigation (RDM).

Dealer Message - Under certain conditions, the cylinder head gasket effectiveness may be reduced which may cause vehicles to experience overheating, coolant loss, misfire, and/or DTCs P0300 through P0304 stored.

Service Bulletin - Under certain conditions, the cylinder head gasket effectiveness may be reduced which may cause vehicles to experience overheating, coolant loss, misfire and/or DTCs P0300 thru P0304 stored.

Service Bulletin - On certain 2018-2022 Accord and 2018-22 Accord Hybrid vehicles equipped with the Wireless CarPlay and Android Auto software upgrade, a programming issue within the Wireless CarPlay and Android Auto software may cause an invalid "License Authentication Error" message to appear on the display audio screen after approximately 1,500 ignition ON/OFF cycles.

Service Bulletin - Honda has developed software updates to the Honda Sensing system to enhance driver experience by modifying the circumstances when the advanced driver assist system (ADAS) decelerates the vehicle or the extent of deceleration. The software covers Adaptive Cruise Control (ACC), Collision Mitigation Braking System (CMBS), and Road Departure Mitigation (RDM).