2020 Honda Odyssey electrical system problems

“My 2020 Honda Odyssey EX-L intermittently fails to restart after the Auto Idle Stop feature shuts the engine off at a red light or stop. This has happened probably 10 times in the past 6 months. In order to start the engine, I must recognize that the engine isn't starting, turn off the vehicle, and turn it back on, often 2-3 times before it actually starts. This leaves the vehicle stopped in a traffic lane at an intersection with traffic trying to pass, which creates a risk of rear-end collision or cars trying to pass me. Cars have gotten into near misses trying to pass me while my vehicle is inoperable. I have no warning lamps or messages before it happens. History: The dealer performed Honda’s idle-stop software update (service bulletin 23-008) in November 2024 at about 63,100 miles. The problem continues. The battery was replaced in December 2022, and the dealer’s October 2026 inspection rated the battery “Good.” (as did a second independent auto shop). At 93,331 miles in October 2026 the dealer documented the complaint, charged a diagnosis fee, and recommended replacing the starter motor at a cost of $954.53 plus a diagnostic fee of $184.95. I contacted…”

“On the middle of July, we were driving and all of a sudden all these lights start coming up the Brake System Warning, Collision Mitigation ,Adaptive Cruise Control (ACC) , Lane Keeping Assist System (LKAS), Road Departure Mitigation System, Auto High-Beam we took it to holler Honda. They said that it was code u3000–49 for forward camera and that it will need to be replaced. They are charging us almost $3000 to get it fixed.”

“While sitting at light, Idle stop engaged and engine stopped - then car lost all power. I was boxed in in heavy traffic and could not move. The car could not be shifted to neutral when I tried to consider how I could get off the road. After a minute or so power suddenly returned to the vehicle and I was able to proceed. The next day, lucklily at a less busy intersection the same issue occurred (again with Idle Stop engaged). After these events I scheduled to take to dealership. Over the next several days I made sure Idle stop was not engaged and had no further issues. Took to Honda dealership and they determined started needed to be replaced. This repair was completed at my expense.”

“Front Camera failure which disables the entire Honda sensing Suite, Shuts down Cruise control, lane keeping assist, front collision warning and Auto emergency braking. This has caused the loss of many safety features intended to prevent accidents and injury. There are numerous warning lights on the dash that are constantly displayed and can be a distraction to other safety or maintenance concerns. Dealer has diagnosed the problem to be an issue with a faulty front camera system. The repair for this is extremely expensive”

“after a heavy rain, the automatic tailgate opening/closing function stopped working. Trunk can only be opened manually. warning message on dashboard: POWER TAILGATE PROBLEM. water intrusion. cracked seals.”

“While Automatic IDLE was on, engine shut down at a red light. Dashboard showed message: put in park. Alternator was fine. Battery fine. I DID get the software update but this happened AGAIN. This time was able to put in park and was able to start the car. I have to remember to turn OFF Automatic IDLE to avoid this from happening again.”