I posted this a few years ago, but the thread devolved into dehumidifiers in the trunk so it kinda went off-topic, but I've never found a solution to the problem, so I'll ask again... I have a message on the dashboard display that says “Key Fob not Detected”, and you can't start the car with the push button. The temporary solution was to pop the button cover off, put the key fob in the slot and turn it like a regular key. That works ok. Then, after starting the car with the fob and turning it off, the message “Service Keyless System” comes up. It's not the fob. Thought maybe it was, but a new battery didn’t help, and I tried my other fob and that didn’t work either. I found a TSB that has that error message listed, #08-047-11 …. (DTC) B25AA-01, B25A9-01, but it seems to be for a 2011, and talks about replacing both door handles with something about the proximity entry system, which my 2010 doesn’t have. I highly doubt that it's software. This just started out of the blue one day, and there's been no updates to the vehicle software, and it's not been to any dealership for service or had any other work done on it. I suppose it could be the key unit in the dash, maybe something in there failed? But it looks like that's a $400 part and probably requires a dealer to tweak the software to work with my car. So I have to admit, I’m stumped. Has anyone else seen this problem?
Check that passive entry is turned on in the Uconnect menu. But, the fact you're also getting the FOB not detected message, there's probably something else going on. Also, your car's security control module can be queried for any error codes. If there is a weak signal from the keyfob, or a possible problem with the antenna that is used to communicate with the keyfob at engine start-up, there is a chance there is an error code logged. I might mention most often, if there is a problem in this area, it is most likely due to someone having been at the area behind the dash and inadvertently disturbing the antenna and its connection. The antenna resides behind the dash ignition switch surround. Do you have access to an OBD2 scan tool specifically for your Challenger? If not, the dealer could test the security system and its RF circuit that interacts with the keyfob and get to the root cause of the problem. You may have a bad WIN module.
