Which parts fail
Components named in complaints (automatic emergency braking, adaptive cruise, lane keeping, backup camera).
Mileage when the problem started
Owner reports
Selected complaints filed with NHTSA by 2021 Honda Odyssey owners, lightly cleaned up (personal details are redacted by NHTSA).
The contact owns a 2021 Honda Odyssey. The contact stated that while reversing, the rear-view camera display flickered on and off. The contact stated that while using the GPS, the display went blank. The vehicle was taken to the dealer, and the dealer attempted to reset the rear-view camera display; however, the failure reoccurred. The dealer was made aware of the failure, and a diagnostic test was scheduled. The vehicle was not diagnosed or repaired by an independent mechanic or dealer. The contact contacted NHTSA Campaign Number: 23V431000 (Back Over Prevention); however, the VIN was not associated with the recall. The manufacturer was not made aware of the failure. The failure mileage was approximately 49,231.
Rear view mirror on the windshield has a factory defect. It falls off and causes hazardous conditions. I backed into a parked and unoccupied vehicle. It was dark, the warning beeper did not sound until I hit the vehicle. The dealership has attempted to fix the issue 3 times, the item is ordered to fix the mirror. I have reported this issue to the NHSTA twice. This is my second update after the initial report. The sales manager, Bobby, (cell#[phone]), says that he is aware that other Honda vehicles have had this problem with the mirror.
The VSA modulator has repeatedly failed. When it fails, all of the safety systems report errors - air bags, ABS brakes, high beams, traction control, blind spot detection, parking sensors, etc. Additionally, the power sliding passenger doors and tailgate will not open, even manually. I have taken it into Honda dealerships on 3 separate occasions. On 6/14/21 (vehicle mileage 7,453) they cleared the error codes and reset the system and reported it was fixed. On 2/26/2022 (vehicle mileage 21,077) it happened again and they reported the VSA modulator as defective and replaced it under warranty. On 7/29/2022 (vehicle mileage 26,916) it happened again. This time the dealership disconnected and reconnected the VSA modulator and it decided it was fixed. At the time of the issue I was driving the van at approximately 30 mph on flat streets through my town. …
After a slight rain, the error of Radar Obstructed is being displayed. Can't get this error removed or fixed. After searching more I found out that: 1. Honda has a defective design in the Advanced Driver Assistance Systems (ADAS) of all Honda Odysseys, models 2018-2023. 2. Namely, Honda has placed the RADAR behind the large HONDA emblem on the front grille. This causes the radar to give a "RADAR OBSTRUCTED" warning, which disables all Advanced Driver Assistance Systems in the car (Automatic Emergency Braking, Adaptive Cruise Control, Forward Collision Warning). 3. The "RADAR OBSTRUCTED" warning cannot be reset by restarting the vehicle or disconnecting the battery, requiring recalibration of the RADAR at the cost of $800 each time since it takes several hours to do (per Dealership). 4. …
I was driving in light snowfall when several alerts notifying me that the radar sensor was not working. This is common in snow fall. Later I cleared off the radar unit cover (The Honda logo on the front of the car). The alerts remained. I took it to the dealer and they dubiously told me it was "damaged by snow". This is impossible. It was light snow. There was no collision or impact. This device should be durable. It has no moving parts. But Honda wants me to believe that it simply stopped working from driving in a light snow. They want $1300 to replace. How do I know the next one won't conk out after the first snowfall? These units should have a lifetime warranty with only exceptions for collisions or impact damage. If the unit is damaged by snowfall, it's clearly too fragile and should not be on the market. …
A few weeks ago, the car I was driving steered itself dangerously close to a pedestrian in the breakdown lane. I was driving my wife's car which I drive infrequently. This model has a lane-keeping function which steers you back into your lane if you veer. I was rounding a bend in the right lane on a highway as a man appeared on the edge of my lane, changing a tire, partially in the roadway. I was pointed away from him so I let the car coast out of his way but the car literally turned the wheel and fought me as I tried to veer left out of the man's way. It all happened in less than a one or two seconds. Had I used the turn signal the system would have temporarily disabled itself. I shared this story on Facebook with my friends and several friends reported nearly identical issues with lane keeping driving them towards a hazard.
While driving in highway construction zones the car's lane departure system attempted to steer the car along lane markings set before the construction zone was established. In several instances this caused my car to steer, contrary to my steering input, towards Jersey barriers and dangerously close to a collision. The car's collision warning and automatic braking systems then engaged and applied the brakes regardless of following traffic. After the first instance, luckily in light traffic, I became aware of this issue and aware of how to quickly defeat these safety systems. After several additional instances, some in traffic at highway speed, I determined the lane departure system was more dangerous than helpful and I suspended it by a simple dashboard procedure. I am now able to negotiate construction zones without issue.
While driving on a straight, wide open road at approximately 45mph with no vehicle in any close proximity in front, the forward Collision Mitigation Braking System alarmed and activated and strongly braked, slowing the car quickly down to about 20mph before releasing. Fortunately, there was no one behind me to react to the unexpected slowing down of my car. There was no apparent reason why this should have activated. The CMBS has activated previously in other non-threatening situations but there was usually a condition where you could justify why it made a mistake, such as being in the left lane of a two lane road which curves to the left and a car in the right lane slows to turn right, my car thinks it is in front of me when it is not. Still, these situations result in a danger of getting hit from behind.
It started that all the sensor in our car started to go off. We were told we had a bad battery, even thought we had replaced it new just last year. Once we had the battery checked and alternator. The sensors started to act up again, out tail gate started to malfunction. Wouldn't automatically close. A few weeks ago driving down the road the tail gate opened and the anti theft system started going off while the car was running and still going. Come to find out there is a water leak in the rear that has gotten into the rear fuse box and has cause substantial corrosion. The latch to the tail gate is broken. Honda is telling us our extended warranty doesn't cover any of this, even though it is common knowledge, that the water leak is a known problem from 2018-2021. We just found out a few days ago.
Once the cruise control is set, it consistently drops below the set speed and surges back up or over the set speed. Set on 62, it drops to 59 or 60, then surges back up to 62 or 63. This happens on perfectly flat roads with no traffic in front or beside the car. The dealership tried to tell me that the camera for the adaptive cruise might be seeing things in its peripheral vision area, but there is nothing there, the shoulder of the road is wide and free of obstacles. I've owned many other brands of vehicle, and never had this trouble with the cruise control on any of them. This is also a safety issue because sometimes it just randomly slows down or speeds up when there are cars behind you or beside you.
Related recalls
Back over prevention › Display function
Honda (American Honda Motor Co.) is recalling certain 2018-2023 Odyssey, 2019-2022 Pilot, and 2019-2023 Passport vehicles. Due to a faulty Media Oriented Systems Transport (MOST) communication coaxial cable connector, the rearview camera image may not appear on the display.
Remedy: Dealers will replace the MOST cable harness and install a straightening cover over the vehicle cable connector, free of charge. Owner notification letters were mailed July 24, 2023.
Collision Avoidance complaints in other Odyssey years
Frequently asked questions
How common are collision avoidance problems on the 2021 Honda Odyssey?
NHTSA has 29 complaints about the driver assistance of the 2021 Honda Odyssey, 20% of the model year's 147 complaints. The component named most often is automatic emergency braking (15 mentions).
Is there a recall for 2021 Honda Odyssey collision avoidance problems?
Yes — NHTSA recall 23V-431 (display function, Jun 15, 2023). Recall repairs are free at authorized dealers.
At what mileage do 2021 Honda Odyssey collision avoidance problems start?
Half of the complaints with a recorded mileage happened before about 49,000 miles, and 50% before 25,000 miles.
Is it dangerous?
Owners linked 2 crashes, 0 fires and 1 injury to driver assistance problems on this model year. If you notice symptoms, have the car checked before driving further.
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.