Theory of Operation
WARNING: This page is about a different car, the 2011 RAM Pickup and 2011 RAM Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.
For the engine to start, the Sentry Key Immobilizer (SKIM) feature of the Wireless Ignition Node (WIN) and the Powertrain Control Module (PCM) must successfully communicate data over the data bus. Once the WIN sends the message that a valid Fob-Integrated-Key (FOBIK) is being used, the PCM and WIN perform a "handshake" routine, encrypted with the VIN, to validate this information, and a match allows the engine to run when the ignition state transitions to START. The repair of this fault is determined by the ability of the WIN and PCM/ECM to complete a successful handshake routine over the bus.