Sentry Key Immobilizer System: Operation

WARNING: This page is about a different car, the 2022 Chrysler Voyager and 2022 Chrysler Pacifica. However, it is still accessible from the selected car via links, so may be relevant.

Starting the vehicle with Keyless Go Mode

To start the vehicle, three actions are required:

Valid FOBIK must be present inside the passenger compartment of the vehicle.
Press the brake switch.
Press the start push button in the KIN.

The KIN then sends a hard wire and a K-line signal to the Radio Frequency Hub (RFH). The RFH starts the handshake protocol with the ignition FOBIK using a secret key through Low Frequency (LF) antennas located in the vehicle; and then the FOBIK responds back with the Radio Frequency (RF) link to RFH. When the RFH verifies the RF link as a valid ignition FOBIK then another handshake using the secret code will start between the RFH, BCM and PCM through the Controller Area Network (CAN) C bus. When the handshake is verified by all three modules, the engine will start. For export vehicles, the Electronic Steering Lock (ESL) is also being used. When the ignition is off, the ESL locks the steering column and prevents the steering wheel from rotating. To start the vehicle, the ESL must unlock first. To unlock, a handshake between the FOBIK and RFH must be completed; and then a handshake between the BCM and ESL through the CAN-C bus must be validated and completed.

Starting the vehicle with Transponder Mode

To start the vehicle, two actions are required:

Press the brake switch.
Press and hold the start push button in the Keyless Ignition Node (KIN) with a valid FOBIK for two seconds.

The KIN sends a hardwire dedicated K-line signal to the RFH. The ISC handshake between the RFH and the ignition FOBIK is performed through small internal LF antennas located in the KIN. When the RFH verifies a valid FOBIK, then another handshake will start between the RFH, BCM and PCM through the Controller Area Network CAN-C bus. When the signal is verified by all three modules, the engine will start. For export vehicles, the ESL is also being used. When the ignition is off, the ESL locks the steering column and prevents the steering wheel from rotating. To start, the vehicle ESL must be unlocked first. To unlock, a valid handshake between the FOBIK and RFH must be completed; then a valid handshake between the BCM and ESL through the CAN-C bus must be completed.

The SKIS performs a self-test each time the status of the ignition switch transitions to On, and will store fault information in the form of a Diagnostic Trouble Code (DTC) in BCM memory if a system malfunction is detected. The hardwired circuits between components related to the SKIS may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring information. The wiring information includes wiring diagrams, proper wire and connector repair procedures, details of wire harness routing and retention, connector pin out information and location views for the various wire harness connectors, splices and grounds.

However, conventional diagnostic methods will not prove conclusive in the diagnosis of the SKIS or the electronic controls and communication between other modules and devices that provide some features of the SKIS. The most reliable, efficient and accurate means to diagnose the SKIS or the electronic controls and communication related to SKIS operation requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.