About this problem
Automatic emergency braking uses a camera, a radar sensor or both to watch the road ahead and brake hard if a crash looks likely. The problem owners report is "phantom braking": the system slams on the brakes for a shadow, an overpass, a parked car or nothing at all. That can startle the driver and risk a rear-end crash from the car behind. Software updates have reduced it on some models but not all.
Across all owner complaints filed about the Honda Accord since 2012, 603 (6.7%) describe automatic emergency braking problems, making it the most reported problem we track on the Accord. The reports cluster on the 2018, 2019 and 2020 model years, and the 2018 drew the most, with 236. It tends to show up early in the car's life: half of the owners who gave a mileage were between 6,000 and 53,000 miles. 33 reports describe a crash or fire linked to it. No recall covers it, but Honda has sent dealers service bulletins about it, listed below.
What owners report
Owners describe the Accord braking hard on its own, often at highway speed with nothing in the way: under bridges, past parked cars, in shadows or around curves. Some report the warning chime and a jolt; others report the car slowing sharply enough to risk being rear-ended. The complaints cluster in the 2018 to 2020 model years, the first years this system became standard on most trims.
How it gets fixed
Carmakers have released software updates for many of these systems, and some owners report the problem eased after a dealer update or a camera and radar recalibration. A dirty or misaligned windshield camera, or a replaced windshield that was not recalibrated, can also cause false alarms.
Typical cost: A software update is usually free under warranty. A camera or radar recalibration after windshield work typically costs $150 to $400 at a shop.
Complaints by model year
In owners' words
"The vehicle had a sudden loss of function in: 1. Road departure mitigation 2. Collision mitigation 3. Adaptive cruise control 4. Braking system the vehicle was in motion at speed of 10-40mph, with air temperature of 28-32 degrees and snowy conditions."
2018 Honda Accord, 14,290 miles
"My 2019 Honda Accord, purchased new july 25, has 2365 miles on it. Twice very early in my ownership of the car the collision mitigation braking system (cmbs) activated with no cars in front of me."
2019 Honda Accord, 2,300 miles
"The warning lights come on for the breaking system road departure mitigation system problem see your dealer, collision mitigation braking system problem see your dealer adaptive cruise control system problem see your dealer."
2020 Honda Accord, 2,516 miles
Excerpts from public owner complaints filed with the National Highway Traffic Safety Administration, lightly trimmed.
Service bulletins
Honda has sent dealers 5 bulletins that mention this problem on the Accord. A bulletin tells technicians how to fix a known fault. It is not a recall, so the repair is usually free only while the car is under warranty or covered by an extension.
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.
American Honda has identified a condition that may affect Collision Mitigation Braking System (CMBS) operation.
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 t...
The adaptive cruise control (ACC) turns off unexpectedly while it is in use, and the Collision Mitigation Braking System problem.
Tech line summary article - We're currently looking at an issue where the vehicle shudders or jerks and various indicators come on.
Government investigations
Engineering analysis EA24002 · 2018–2022 · opened Apr 2024
Preliminary evaluation PE22003 · 2018, 2019 · opened Feb 2022, closed Apr 2024
Before you buy a Accord
- Drive the car on a busy road with parked cars, overpasses and shadows, where false braking tends to happen.
- Ask whether the braking software has been updated, and check for open recalls by VIN.
- If the windshield was replaced, ask for proof the camera was recalibrated.
Questions
Which Honda Accord years have automatic emergency braking problems?
Complaints are highest for the 2018, 2019, 2020 model years. The 2018 drew the most, with 236 reports.
At what mileage does it usually start?
Among owners who gave a mileage, the middle figure was about 20,000 miles, and half reported it between 6,000 and 53,000 miles.
How much does it cost to fix?
A software update is usually free under warranty. A camera or radar recalibration after windshield work typically costs $150 to $400 at a shop.