Epilogue: I bought an OEM door latch from an online dealer and installed it myself. The problem is now solved.

It was apparently an internal electronic failure in the latch assembly. The job wasn't hard at all except for one particularly reluctant fitting on the cable that goes to the outside door handle. Other than that, it was all very straightforward and logical -- a rather simple job to save $800.

 

Thanks for the follow up!

 

Thanks for this! Always good to have someone post the solution to a problem. And great job on the DIY repair, excellent!

 

I actually have the same problem but can't tell if it's the passenger door lock or the drivers door lock. When you locked your door did BOTH the driver and passenger door not lock or just the passenger door?

 

Both of my doors locked just fine. The only problem was that the mirrors wouldn't fold upon locking and the car would emit a double beep to signal an issue. They only way I was able to find the source of the issue was to take it to the dealer. I don't know what diagnostic tools they used but they told me they could fix the issue by replacing the passenger door latch assembly.

 

I’ve switched my car key battery is it because of this and also I had a car washed and I heard the alarm was going off when the person was washing it not sure why and then a day or 2 the beeping thing and side mirrors weren’t closing