intermittent starting problem

the black battery cable 1/0 wire (fat) connects to the frame at a spot that must be wirebrushed clean and re-assembled...also the 1/0 cable leading to the motor block (near the alternator) must be corrosion free before bolting them back together~

Got a 2006 Chrysler 300 touring. This might sound crazy -- I thought it was -- but I know these cars have very sophisticated anti-theft starting systems. My car was having intermittent starting problems. Off and on. Then I realized something -- the spare key was on the same key ring as the main fob. I removed it and tried again. It started right up and kept running. The next few days, I started it every two hours, started right up and kept running. If I try to start it with the spare key, it starts but shuts right down. I think, in my case, the starting system was sensing the spare key which was right next to the main key and wouldn't accept it. Since that key has been removed from the fob, I haven't had a single problem. In my case, it's a bad spare key adjacent to the main key. The anti-theft system must be sensing it and shutting it down. Have thrown away that key, and haven't had a single issue since. Anyone having this problem, please check your key ring for a spare. It worked in my case, and may work in yours. Good luck.

My 2014 300S has had several occasions where my wife uses the second FOB and the next morning when I get in to start the car if simply does not start from my FOB. I sit, wait a few minutes then it engages my fob and starts - very annoying!! This happens every time we switch FOBS? is it FOB or the car software?