BOTTOM LINE:    DON'T BUY USED CHRYSLER FOBIKS!!

THEY CAN NOT BE RE-PROGRAMMED TO A DIFFERENT CHRYSLER VEHICLE.

ONLY NEW A FOBIK CAN BE PROGRAMMED TO A CHRYSLER WIN MODULE - USED ONES CAN NOT.

Some sellers on eBay sell used FOBIK KEYS.  DON'T LET THEM TAKE YOUR MONEY AND THEN SAY "WE SAID TO CHECK WITH THE DEALER".

How the FOBIK works:

When you insert your key, the Wireless Ignition Node (WIN) checks through its antenna with the Sentry Key transponder within the FOB with Integrated Key (FOBIK) using a Low Frequency signal. When you put in your key, the transponder chip is within the range of the WIN transceiver antenna ring.

The WIN decides if your FOBIK is present in the ignition switch based upon the signal from the transponder and then decides if your FOBIK valid.  If it is valid, then the WIN tells the Powertrain Control Module (PCM) over the CAN data bus this is a valid key.  Then, the PCM allows the engine to start.

If the PCM receives an invalid key message, or receives no message from the WIN over the CAN data bus, the engine will be disabled after a very brief time. 

Each Sentry Key FOBIK has a unique transponder identification code permanently programmed into it by the manufacturer. Likewise, the WIN has a unique Secret Key code programmed into it by the manufacturer. When a Sentry Key FOBIK is programmed into the memory of the WIN, the WIN stores the transponder identification code from the Sentry Key FOBIK and the Sentry Key FOBIK learns the Secret Key code from the WIN. Once the Sentry Key FOBIK learns the Secret Key code of the WIN, it is permanently stored in the memory of the transponder. Therefore, once a FOBIK has been programmed to a particular vehicle, it cannot be used on any other vehicle.

The FOBIK transponder cannot be adjusted or repaired. If ineffective or damaged, the entire FOBIK and RKE transmitter unit must be replaced.