The immobilizer system consists of a passive challenge-response (mutual authentication) transponder inside the key head, the encoded SMARTRA3 unit /key and the PCM/ECM can decode the secret code stored in the SMARTRA3.The PCM/ECM carries out the immobilizer function, the SMATRA3 management and the key management. The immobilizer function is the unlocking of PCM/ECM only after detection of a valid ignition key /the SMATRA3 and the locking of PCM/ECM after switching off the engine. The PCM/ECM communicates the encoded messages to the SMARTRA3 via a dedicated communication line and confirms the key with the SMARTRA3. The PCM/ECM related to immobilizer has the 3 kinds of software. At the first IGN on, the PCM/ECM concludes the software of each option (smart key, non-encoded SMARTRA3, encoded SMARTRA3) by communication. It is called “The autodection for PCM/ECM”The PCM/ECM keeps the previous option before being neutral when it is setted to each option.

The PCM/ECM sets DTC P1610 if Non Immobilizer EMS is installed on vehicle equipped with Immobilizer.

Fig.1) A normal signal waveform of antenna and immobilizer communication when IG key (TP : Transponder) is OFF to ON.