I have a 2018 Accord Sport, recently bought as Certified used.
When using either the fob or the driver's armrest lock button, one of four doors will not lock or unlock. The failure moves from door to door.
When bought last month, the fob appeared to work to lock and unlock all doors.
There was one instance where the fob didn't unlock the car until I pressed the lock button, then the unlock button. I dismissed this as a glitch.
Last week I noticed that the fob wouldn't lock or unlock the driver's door. Using the mechanical key worked to lock and unlock the door. Using the door handle also worked to unlock the door. Using the manual lock at the door handle also worked. Using the armrest button (driver or passenger) wouldn't lock or unlock the driver's door, but did lock/unlock the other three doors. My first thought was that the actuator was broken.
However, while trying the fob and the armrest button, reading the manual, and checking settings in the touch screen display, at one point the driver's door started working again, but the front passenger door lock stopped working at the same time. The fob and both armrest switches wouldn't unlock the passenger door, but would unlock the other three doors.
Yesterday, while using the car, the front passenger door lock started responding again, but the right rear door stopped locking and unlocking, except with the manual methods.
Today, while checking before I wrote this, the failure was still at the right rear door, but then moved back to the front passenger door, and the rear door works again...

I can only imagine that it's either a software issue, or there is a relay that provides power to the actuators and it can't power all four at the same time so only three respond. I'm not sure of the locking mechanics and system architecture.

Since the car is Honda Certified, I'll take it to the dealer under warranty. I'm worried that they won't listen to me and will just replace the actuator that currently doesn't work and won't really fix the problem.

Any thoughts on suggestions to the dealer to find the real problem? Anyone else seen this door lock failure that moves from door to door?

 

welcome to the forum. i have not have that happen to any of my Hondas. Being it is a certified vehicle, take it back to the dealership and copy what you have here without the comment about the dealership and ask them if they can fix what is going on. let them figure out what is causing this. they may have all the old previous records of the vehicle. if you can document the dates and times of when this happens it will help them to trouble shoot cause.