Honda Collision Mitigation Braking System Problems: What You Should Know
Many reports of sudden braking in Honda vehicles involve the Collision Mitigation Braking System (CMBS).
CMBS is designed to warn drivers of a possible collision and, if needed, apply the brakes to reduce the severity of a crash. However, consumers report the Honda Collision Mitigation Braking System problem causes vehicles to slam on the brakes with no obstacle ahead, and Honda’s own manual says the system may activate at speed bumps, road work sites or train tracks.
Honda CMBS FAQ
A braking system that stops your Honda with nothing ahead is a safety problem, not a quirk. The answers below cover which Hondas are affected and how Honda has responded.
What Vehicles Have Problems With Honda’s CMBS?
Honda’s Collision Mitigation Braking System is part of Honda Sensing, which Honda made standard on every 2020 CR-V. NHTSA’s open investigations into braking with nothing ahead include these models:
- Honda Accord and Accord Hybrid, 2020–2022
- Honda CR-V and CR-V Hybrid, 2020–2022
- Honda Passport, 2020–2023
- Honda Insight, 2020–2022
Owners of newer Pilots have filed similar complaints with NHTSA, although the Pilot is not part of those investigations. One 2024 Pilot owner reported that the SUV braked on its own twice at 60 mph on the interstate with no one nearby.
Random braking and other brake issues have landed some of these vehicles in class action lawsuits. In one of them, the class includes 2020 Accords bought new in California, and the parties reported a settlement to the court in October 2026. Insight and Passport models from 2020 to 2022 were among the vehicles named when a separate proposed class action was filed in 2024.
Honda models not included in these class action cases may still have a recurring CMBS problem. If your Honda could be part of either case, ask a lawyer about any opt-out deadline before you file an individual claim.
If you live in California and your 2020 or newer Honda, bought or leased from a licensed California dealer, keeps braking on its own, Lemon Law Help may be able to help with an individual lemon law claim. A lawyer can also tell you whether your vehicle is part of a class action you may need to opt out of first.
What’s Wrong With Honda’s CMBS?
According to multiple class action lawsuits, a Honda Collision Mitigation System problem can cause various issues. These problems include random engagement of the brakes and sudden deceleration.
Supposedly, the CMBS provides false alerts for obstacles that are not present. Some Honda owners and lessees state that their vehicles’ CMBS mistakenly reads oncoming traffic as an obstacle in their lane. Honda’s owner’s manual for the 2020 CR-V says weather, light and roadway conditions can affect how the CMBS works.
Conditions may include bad weather, sudden changes between light and dark, shadows, low sun at dawn or dusk, and roadway objects mistaken for pedestrians or vehicles. The manual says these conditions can shut the system off or limit some of its functions.
Other Honda Sensing systems have had problems too. A Honda service bulletin says the lane keeping warning light on some 2023 to 2025 CR-V and CR-V Hybrid models can come on in reverse because of false detection in the camera software.
Recurring Honda Sensing problems, in particular Honda CMBS problems, may turn your vehicle into a lemon. If that is happening to you, contact a lemon law attorney to discuss your legal rights.
How Does the Honda CMBS Work?
Honda’s Collision Mitigation Braking System is an autonomous emergency braking system that incorporates features of the Forward Collision Warning (FCW). Part of Honda Sensing, the FCW is designed to warn drivers of a possible collision. In the 2020 CR-V, for example, these systems rely on a radar sensor in the front grille and a camera behind the rearview mirror.
By detecting possible obstacles, Honda’s Forward Collision Warning System warns of a possible frontal collision. Upon detection, the Honda FCW provides the driver with visual and audible warnings.
If a driver ignores these warnings or otherwise cannot respond in time, the Honda CMBS will continue these alerts. Simultaneously, the system will apply light braking and, if a collision is unavoidable, apply hard braking to lessen the impact of a crash.
Other technologies included in Honda Sensing include:
- Road Departure Mitigation System (RDM)
- Adaptive Cruise Control (ACC) with Low-Speed Follow
- Lane Keeping Assist System (LKAS)
These systems are supposed to help control vehicle speed, help keep the vehicle in its lane, and alert drivers if they are at risk of crossing into adjacent lanes.
The Sensing technologies do not always work as intended. The Honda brake system problem may make the vehicle unsafe to drive. At this time, your Honda Accord, Honda CR-V, Honda Pilot and other Honda vehicles can be affected.
How Has Honda Responded?
In 2024, NHTSA upgraded its investigation of the Accord and CR-V to a deeper engineering review and expanded it to 2020 to 2022 models. Honda told NHTSA, as it also did for the Passport and Insight, that some customers possibly did not fully understand the system and its limits. NHTSA also noted that, according to many complaints, Honda dealers couldn’t reproduce the problem or called it normal system operation.
In July 2026, Honda announced a Honda Sensing software update, including the Collision Mitigation Braking System, for certain 2020 Accord and Accord Hybrid models, which dealers install at no charge. Honda’s letter to owners says the update changes when the system slows the car, or by how much. It is a product update, not a safety recall, and NHTSA’s recall records show no Honda recall for this problem in 2020 or newer models.
A second NHTSA investigation covers the same problem in the Passport and Insight, and in 2025 it was expanded to 2023 Passports. Both investigations were still open in October 2026. NHTSA’s service bulletin records show no Honda software fix for unexpected braking in the Passport, the Insight or the Pilot as of that month.
Is My Honda a Lemon?
Honda’s CMBS may have turned your vehicle into a lemon if your vehicle shows the following problems:
- Sudden and Unexpected Braking
- False Obstruction Alerts
- Lane Keeping False Alerts
- Unexpected Highway Speed Fluctuation
Recurring problems with your Honda’s Collision Mitigation Braking System can make your vehicle unsafe to drive. If Honda or its authorized repair facility cannot fix a covered problem that substantially impairs your Honda within a reasonable number of attempts, your vehicle may be a lemon.
The number of repair attempts considered “reasonable” can differ on a case-by-case basis. Consult a California lemon law attorney about your situation and legal rights. If you are included in one or more class action lawsuits, you may need to opt out before certain deadlines to retain your individual right to sue.
How Do I Opt Out of a Honda CMBS Class Action Lawsuit?
If one or more class action lawsuits cover your Honda, you may opt out and bring an individual lemon law claim against Honda instead. You may need to opt out before a certain deadline to retain your individual right to pursue a lemon law claim if you are included in at least one lawsuit.
Once you opt out, you can bring claims that fit your own situation. Contact a California lemon law attorney if you experience Honda brake system problems and want to learn about your own lemon law rights.
Lemon Law Help works only in California. We help California residents who bought or leased a defective model year 2020 or newer vehicle from a licensed California dealer. We cannot help people outside California, unless they are active-duty military.
If you go forward with a case, we represent you at no cost and work to get cash compensation, a replacement or a buyback. Contact Lemon Law Help today.
