Ok, I bought this STS about two months ago and am having a heckuva time trying to get anyone to work on it or find any advice on where to start without throwing parts at it which I cannot afford to do. It all started with the front door locks not working with the keyfob unlock button and wouldn’t open without using the manual key and then almost immediately afterwards I ran into the “keyfob” not detected message and after replacing the batteries in the fob and reprogramming the fob it seemed ok for a few days and then was “hit and miss” as it seemed to keep forgetting the programming and left me in a parking lot a few times trying to reprogram my fob as the car stated “no five detected”. The last time I drove it I left the car accessories on with the key in the fob holder which is located in the console while running into the store (to try and prevent from being stranded again) and when I came out the car wouldn’t start and I haven’t been able to get it to start since. I’ve unhooked the battery, tried resetting the fob which it IS recognizing but When I hit the push button start, everything seems fine and the gauges move from left to right like it’s starting but nothing happens but a light “thump” from the starter. I actually tried to bypass the starter relay and use a wire to jump it over and see if I could get the starter to work and still nothing. Starter had given me no problems besides a few drags after starting prior to this issue but with 123k miles I guess that’s a possibility but I also keep seeing ECM/PCM answers when doing research on what’s happening. Also, just adding something here so if someone is nice enough to help me they have ALL the info, the car didn’t have any aforementioned issues until the prior owner said she lightly backed into something in a parking lot which resulted in a minor dent in the trunk lid but did result in the backup “beep signal” to stop working and since then it seems to also drain the battery after about 4-5 days if the cars not started and driven periodically. Sorry for the overload of info but I’m desperate to get this fixed as it’s my daily driver and I honestly can’t get anyone to say they’ll work on it but a Cadillac dealer which is 45 miles away which means a hefty tow right off the bat and I honestly don’t think that’s an option for me right now financially. Thanks in advance for some great info that I’m hoping to receive.