Tuesday i got home from work i have a TLX it’s a 2019 V6 FWD Aspec i was watching tv and my alarm started going off and when i went to try to turn off with my fob it didn’t respond so i had to take key out an manually unlock and alarm turned off so i unplugged battery for 20 min because this happened before when the battery was dying just to reset thinking it might be the car battery itself even though i just replaced 4 months ago and i replaced the battery in the fob just in case that was going bad and for some reason caused an issue…when i went to hook battery back up it went into auxiliary mode with the lights on, radio on and dash on and i noticed there was a flashing green key on the dash but nothing else just looked normal…i went to try to start the car and it wouldn’t turn over it was trying to and it started flashing a no key detected symbol and then said keyless system start problem so i tried to turn car off and it wouldn’t turn off either i had to unplug the battery again…now every time i hook battery back up it goes back into the auxiliary mode and can’t turn car on or off so i have to keep battery unplugged…when the car is in auxiliary mode i try the buttons on fob the left light will flash amber once and then far right light will flash red 3 times from my understanding which means key isn’t connected…even if i hold the fob to the start button it won’t read it…i was thinking maybe fob failed so i have 2 others that the car came with that i had in drawer without batteries so i put fresh batteries in each of those and neither one would connect to car either remotely or when held to start button…so i have no clue what to check really at this point…i was thinking of calling a locksmith to come and try to reprogram the fob but even he mentioned it was odd that all 3 wouldn’t be connecting but was thinking maybe something like the transmitter failed? Has anyone had an issue similar to this? Any suggestions on any fuses i could check? Where is the transmitter in this TLX? Is it the start button? I went and even got the car battery tested and it tested fine with the handheld voltage check and a load battery test. Is there anywhere i can stick the physical key to try to start or is that just for the doors? I can’t get into my mechanic until next week so I’m just seeing if there anything else i can check until then from what I’ve been reading I’ve seen similar issues with people saying their keyless control unit failed, another said they took out fuse for alarm and it fixed which what fuse would that be? Another for an older year said maybe the BCM failed or fuse failed but I’m not seeing where that is for this car? Also since it’s stuck in auxiliary mode how do i get it into neutral if there’s nowhere to put the key to manually start it? Thanks