All right, I've got an interesting one for you guys. Did some forum searching and found things related to parts of my problem(s), but not all, so I decided to make my own post. As usual I'll try to provide as much info as I can as opposed to not enough, so apologies in advance for the length, but not for any dry humor.
TL;DR: keyless entry is not/barely working, fob batteries replaced with no real change, physical key does not work in the door, but remote starter works fine and does unlock the door. Interior door lock buttons and locks themselves work normally. Makes zero sense. Lots of cussing.
For background: It's a 2016 FR-S, auto. Being what it is there's no fancy BRZ-like fob, push-button start, no alarm system, etc., it's a keyed ignition and I've got the keyhole in the driver's door for manual operation of the door lock when needed, like the peasant I am. I do have the newer style (larger) Toyota/Scion key compared to the earlier version, so there are still keyless entry buttons, and I have a second spare key that I can count on one hand the number of times I've used, so it's essentially still brand new. I also have a valet key. The door lock actuators were both replaced last spring because the driver's side started going bad and not locking the door. No issues with that since. Final thing of note is when I took delivery of the car the dealer installed a remote start system (and I cannot tell you what form of witchcraft was performed behind the dash to make that happen, but it's there and it functions), so that's been on the car for the now 6 years I've owned it.
Okay, to the issue: After being away from home from the end of the summer until mid-December, though the car was garaged I was not able to put it on a maintainer, New England still manages to get ugly cold, and the battery died. Obviously keyless entry is a no-go in that situation.
My first real problem was that when I went to put the key into the door lock to manually open the lock, nothing happened. I can move the key in either direction, but it does not actuate the lock one way or the other. Pretty sure that's not supposed to happen even with a dead battery. I get the electrical side of things not functioning, but the whole point of the mechanical backup is pretty much this exact situation.
Needing to access the hood latch so I could get the car jumped, I was still able to open the trunk with the key and...do the needful. Car seems fine after getting jumped and a good long drive to recharge the batt. The key in the door still will not move the lock, but the keyless entry buttons are working fine for the doors and trunk lid.
About a week ago I noticed that the keyless buttons didn't seem to be working consistently, took a few presses sometimes, and as I was usually walking toward the car when this was happening I assumed the fob battery might be on its way out. Adding to my suspicion was being outside in temps around freezing, and though the key was in a pocket, two instances of that behavior were after being out in the cold and I figured it was killing the fob battery. But it has started to occur at other times and even on warmer days, could be shortly after driving the car and coming back to it or after it's sat for some time, even overnight. I can be standing right by the car door and get nothing. There doesn't seem to be any real rhyme or reason to it for when it happens now. Again, not being able to use the key in the door was problematic in these instances, because I wasn't always in my driveway worried about not being able to get into my car.
What I did find is that I can use the remote starter to start the car, and the fob for the remote starter is also used to unlock the door with a long button press once the car has been remote started. (After that, key has to go into the igntion, turned to On, and the brake pedal pressed in order for the car to stay running and be on your way.) After that the car runs and drives fine, but after shutting it down no guarantees that the key will lock or unlock the car. Honestly I do not use the remote starter very often at all, 99 times out of 100 I'll just open and start the car normally. When in the vehicle, whether it is running or not the lock switches on the door and the locks themselves operate exactly like they're supposed to.
I did replace the key fob batteries today on both keys (and in the short time of maybe 5 minutes going into and leaving the store to buy them, I came out to find the key fob not responsive, but had left the door unlocked just in case), but no change to the behavior. I pressed on the buttons a ton of times and finally got a response from each key, but that's not normal nor something I'm about to start dealing with regularly. I took the battery maintainer off the other car for tonight and hooked it up to this car to charge overnight, so I'll at least try to rule out the battery not being well charged causing some of the issues. But the part that really has me stumped is why the key is not working in the door anymore. That to me is unrelated to any possible electrical issues, because that should be strictly mechanical like it is for the trunk lid. I could be dealing with two or more issues that just happen to be affecting the same system.
If anyone on here has any advice, suggestions, more questions, your time and effort is much appreciated. I want to get a handle on this ASAGDMFP and try to narrow down what the issue(s) may be.
