I've had many kessy problems, too.Guys, thanks a lot for this post.
I have run into faulty door handles on 3 of the 4 doors on my 04 v8. Keyless entry works only on the driver's door. Dealer wants over $2K to replace the door handles and my KESSY is going crazy when driving. I am GUESSING that it is a faulty door handles sensors because MFI keeps telling me to "put selector lever in P", which is also accompanied by an erratic clicking noise coming from KESSY module or the module adjacent to it. Clicking is also observed when the vehicle is not running and key is out of the ignition. Recently, as a result, I have started experiencing rapid battery drain (overnight), which I am guessing is related to the same issue.
As I do not care for the keyless access, I am wondering if I can simply cut/disconnect the wiring to the handles, similarly to the above. Will that affect the vehicle in any way negatively, or is it just going to stop me from being able to use this convenience feature, and avoid the battery drain problem.?
However, I wanted to talk about the "put selector lever in P". I have had that happen a bunch of times, too, if the system doesn't register the lever going to park. In my case, I observe that when the button on the shifter doesn't released when in park (i.e., the button is still depressed). A quick tap of the handle usually releases the button and clears the message.
There's also some actuators in the gear shifter that "click". Notably when depressing the brake pedal, that releases the gear shifter to allow it to move out of P. The kessy module isn't clicking - but perhaps this is. Sounds like you have a couple things tied to the gear shifter and perhaps not to Kessy (not saying you don't have Kessy issues, too - but sharing some stuff I learned that might help in diagnosing what may be two different issues).