Immobilizer System: Notes

DESCRIPTION - IMMOBILIZER SYSTEM 

Courtesy of CHRYSLER GROUP, LLC

1.	Refer to: BODY CONTROL MODULE (BCM) .
2.	Refer to: LOW FREQUENCY (LF) ANTENNA .
3.	Refer to: RADIO FREQUENCY HUB (RFH) .
4.	Refer to: KEYLESS IGNITION NODE (KIN) .
5.	Refer to: INSTRUMENT PANEL CLUSTER (IPC) .
6.	Refer to: POWERTRAIN CONTROL MODULE (PCM) .
-	Refer to: KEY FOB WITH INTEGRATED TRANSPONDER CHIP .

OPERATION 

This vehicle is using Advanced Encryption Standard (AES) to implement the immobilizer system. Secret codes are stored in the RFH, BCM, and the PCM that allows these modules to execute the MiniKrypt immobilizer routine. The key fobs, via transponder mode only, are married to the RFH.

If the vehicle is remotely started, this is a mode that is recognized by the immobilizer system and it will not being authentication until after the vehicle exits from the remote start mode.

The immobilizer process does not take place until after the Security Gateway Module (SGW) has been successfully authenticated. For information regarding the SGW and its role in vehicle security on this vehicle. Refer to MODULE, SECURITY GATEWAY (SGW), DESCRIPTION AND OPERATION .

The immobilizer authentication process is as listed:

1. Start button is pressed
2. The RFH and the LF antennas work together to authenticate the key fob.
3. If the key fob is authenticated as valid, the RFH sends an ignition request signal to the BCM. However if the key fob is not authenticated, this process stops and the BCM does not receive the ignition request signal.
4. When the BCM receives the ignition request signal from the RFH, the BCM initiates the MiniKrypt code exchange with the RFH.
5. RFH responds to the BCM MiniKrypt authentication challenge. If this exchange is unsuccessful, the BCM will stop processing the ignition command. If the exchange was successful, the BCM next determines if ESL is equipped on the vehicle.
6. If the vehicle is equipped with ESL, the BCM will then send an unlock signal to the ESL. If the ESL is not able to successfully unlock, the BCM will stop processing the ignition command. If the ESL is able to successfully unlock, the ESL responds to the ESL unlock challenge.
7. When the BCM receives successful ESL unlock challenge response, the BCM sends a CAN C ignition run/start command to the PCM and then activates its own internal ignition relays.
8. The PCM initiates a MiniKrypt exchange between it and the BCM based on the run/start signal command sent from the BCM.
9. The BCM responds to the PCM request with a verification acknowledgment, thus allowing the PCM to start the engine. If for any reason that the PCM/BCM MiniKrypt exchange was not successful, the PCM will shut the engine off after two seconds and report this back to the BCM. If the exchange is successful, the engine will continue to run.

If the authentication between the BCM and PCM has failed, an new ignition cycle is required to being the process once again. The PCM will allow up to 6 consecutive engine running attempts before it disables the starter motor and requires that a new key be authenticated.

The BCM controls the IPC immobilizer warning lights. When the ignition state changes to RUN or START, the BCM sends a command to the IPC to illuminate the immobilizer indicator for 3 seconds. The BCM keeps the indicator lamp off unless there is an unsuccessful validation. At this point, the BCM commands the IPC to illuminate the immobilizer indicator.