Even though the sensors are less than a year old I thought maybe just one going bad could throw it off, so I had them all checked. Both the tire store that installed the sensors and the Chrysler dealership I went to for the reset afterwards said the sensors were working fine. The dealership did say initially they thought the receiver may be at fault, but then they came back and said it was fine too. They think the error codes reflect a communication problem which prevents the reset. I'm having difficulty locating the P23xx error code(s) on any list I find on the Internet. Is one available? Oh and I did download the info on the RCM repair. So yeah, now I should have a spare. Thanks!