"Keyless System Malfunction" warning on dash (2019 CX-5)

I have a 2019 cx5, and I just took it to a body shop to repair some dents and scratches on the passenger side door and front fender. Car did not have this error when I turned the car in, but once I picked it up from the shop, I have this error on the dash.

Symptoms of the issue are that I cannot use the button on the outside door handle to unlock the doors. Also, the automatic lock when I walk away from the car does not happen either.

Before I go any further, does anyone know of any fixes? Just googling the that dash error, a lot of people have mentioned checking the fob and car batteries (both are fine), and then disconnecting the car battery to reset the car ECU. It seemed like no one really knew what was going on and just throwing suggestions out there. Of course, no one who encountered this problem reported back whether any of these proposed fixes actually fixed the issue. That said, I disconnected the car battery for an hour since it was the only consistent suggestion, and yet the issue persists.

I checked for codes on my OBD scanner and it gave me "B1210-1F" which, after googling, seems to be some short circuit in the keyless entry system.
More googling found this 2014 Mazda 6 troubleshooting guide specifically for that error code. I also found this keyless antenna removal/installation guide for the CX5, but not in conjunction with the error code.

Is there a place I can check error codes online where I can get CX5-related troubleshooting? Or can anyone confirm that the CX5 service manual link I posted even what I need to be doing to hopefully repair this?

Or, ignoring any of my own research and leading questions, does anyone have any suggestions for how to fix this issue? Dealer is an hour away, would like to avoid going to them. Also, not sure whether the body shop I worked with would know how to fix this, or whether it's worth it to go back to them and ask them to help fix? Many thanks in advance for any suggestions you can provide
I read several convos that had this problem. Doesn't look like anyone fixed it. But, would love to know if anyone did. My situation is as others - car was fine, running with no problems. Last night, I went out to close the windows and the car wouldn't start. The FOB batteries are new, the battery was replaced in March 2023. Called AAA for a jump. Ran the car for about an hour - there were several malfunctions listed on the dash, but after awhile they all cleared out except the small yellow triangle and the Keyless Entry Malfunction message.

This morning started the car no problem, but the message and light are still there. Any new ideas?
 
Presently have vehicle at actual Mazda dealer and after a day and a half they can't figure it out either....will try to remember to post resolution if there ever is one.
Background was that vehicle (40K m) was running fine, then wouldn't turn back on, even with a jump. Messages seemed to go haywire, while connected to external power source, from "coolant overheating" to every other message, it seemed.
(Tows through USAA, their jump vendor took 90 minutes and their tow guy after that took another 2 hours w repeated delays. This was all before 7 pm. It seems unrelated but it's actually directly related of course! If you are reading this, AAA may now be superior to USAA for these services in terms of timeliness.)
 
Presently have vehicle at actual Mazda dealer and after a day and a half they can't figure it out either....will try to remember to post resolution if there ever is one.
Background was that vehicle (40K m) was running fine, then wouldn't turn back on, even with a jump. Messages seemed to go haywire, while connected to external power source, from "coolant overheating" to every other message, it seemed.
(Tows through USAA, their jump vendor took 90 minutes and their tow guy after that took another 2 hours w repeated delays. This was all before 7 pm. It seems unrelated but it's actually directly related of course! If you are reading this, AAA may now be superior to USAA for these services in terms of timeliness.)
Thank you for taking the time to reply. We are scheduled to take our car to the dealer in a few days. They said they can reset the system...We'll see.
 
I just registered to see if I can help anyone who is having this problem as I just had it fixed.
I just received my 2018 mazda3 from bodywork repair on driver side fender and front bumper. The key fob was working but I could not use the buttons on the door or hatch. The walkway auto-lock feature was not working either. Finally I had the red key notification on the dash and the message on my entertainment center that the keyless system was malfunctioning and to take it to the dealer.
I took it back to the body-shop and they told me they had forgotten to reconnect a wire they had unplugged after taking off the driver side door. They fixed it in 15 minutes. I have seen someone on reddit who fixed this similar problem themselves by removing the driver side door panel and finding the unplugged connector. I hope this helps.
 
I had written in on this thread several months ago reporting that messages were going haywire suddenly; FOB wouldn't work and vehicle would not turn on even with a jump. It turned out that after a battery replacement and software update the FOB problem disappeared.
A few weeks after that event, had to get door replaced after a hit and run (all this happening on NYC streets btw!). They replaced the door but after that, the cruise control stopped working. Now I'm getting messages about the brake system, and most recently a rear brake light (extremely expensive to replace, btw! It's the whole unit, not a bulb) is flickering.... then multiple lights in rear of car flickering on and off, and also at varying degrees of brightness. Mazda dealers want to keep it for up to 3 days with no loaner (Morristown and Greenbrook) to "check it out", and local garages are suggesting I start by replacing rear tail light unit and see what happens. Just reading through the above messages makes me wonder if it could be that the body repair place in Greenbrook forgot to plug a wire in when they replaced the driver's side door that was damaged. Any thoughts? I used to have electrical problems with a Subaru, which never ended, and was hoping it was a Subaru thing! Thanks.
 
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