2017 Honda Civic. Changed the battery in the fob and still won’t work, it will open the trunk and unlock the doors but does not lock the doors. (Every once in a while it will lock them) I took the fob back apart and everything appears okay inside. The other issue is lately the alarm just randomly goes off and I suspect maybe the hood release may be the problem because the light comes on the dash when you open all 4 doors and the trunk but not the hood release and it has a sensor on it. This is my step sons car and tomorrow he will get his other key fob and can see if that works but still baffled by the alarm randomly going off.

The alarm on my work truck does the same thing at times. The hood ajar message started coming on the dash. When that warning comes on the alarm will go off within an hour of looking the doors. Mine has a kinked wire on the harness leading to the sensor.

Not a second set of keys in that car by any chance?

did you do the key fob hokie pokie ?

https://www.dchkayhonda.com/service/service-faqs/open-honda-key-fob-replace-battery/

you have to reprogram them after you replace the battery on a lot of them now 2017 Honda included

son works at the hardware store and a guy had a 2014 corvette that was bad but they keep getting worse , they are now asking if people have looked up the reprogram sequence before they help them replace the battery , sometimes you need more than just the fob and a new battery to run the program

making a 3rd set of key and fob before you need it is also smart.

No the second set of his keys was at his place which he is gonna try tomorrow. Green county I tried a couple different techniques with the keys which neither worked and seemed like they wouldn’t lol. He bought this car brand new and has never replaced the battery so I wonder if that would cause the alarm issue?