Transponder Key - Operation

OPERATION

When the ignition switch is turned to the ON position, the Wireless Ignition Node (WIN) communicates through its antenna within the FOB with Integrated Key (FOBIK) using a Low Frequency (LF) Radio Frequency (RF) signal. The WIN then listens for a LF response from the transponder through the same antenna. The Sentry Key transponder chip is within the range of the WIN transceiver antenna ring when it is inserted into the ignition switch.

The WIN determines whether a valid FOBIK is present in the ignition switch based upon the response from the transponder. If a valid FOBIK is detected, that fact is communicated by the WIN to the Powertrain Control Module (PCM) over the Controller Area Network (CAN) data bus, and the PCM allows the engine to continue running. 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 about two seconds of operation. The Electro Mechanical Instrument Cluster (EMIC) (also known as the Cab Compartment Node/CCN) will also respond to the invalid key message on the CAN data bus by flashing the security indicator ON and OFF.

Each 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 FOBIK, and 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. (Refer to Wireless Ignition Node Receiver - FOBIK Trapped in WIN) Component Tests and General Diagnostics