• The immobilizer system is a vehicle theft prevention device that only allows keys that have previously been registered to the vehicle to start the engine and prevents it from being started in any other manner (such as with an unregistered key or by starter relay short).

• The immobilizer system consists of the key (built-in transponder), coil, keyless unit, PCM, and security light (in the instrument cluster).

• Ignition keys for use with the immobilizer system have an electronic communication device (transponder) built into the key head that retains specific electronic codes (key ID number).

• The immobilizer system operates automatically when the ignition switch is turned to the LOCK or ACC position. When this occurs, the security light flashes repeatedly 0.1 s every 2 s.

• In order to start the engine, the immobilizer system must be made inoperable using a key previously registered with the vehicle. No special operation is required to release the immobilizer system but rather the vehicle is started similar to vehicles without the system: the ignition switch is turned from the LOCK or ACC position to the ON or START position and the release operation begins automatically. The engine can only be started after the key, keyless unit and PCM successfully perform their parts of the verification procedure. For details, refer to "IMMOBILIZER SYSTEM OPERATION".

• If the immobilizer system is not released due to a malfunction or verification failure, the security light in the instrument cluster displays a DTC. At the same time, DTCs are stored respectively in the PCM and keyless unit. The stored DTCs can be verified using the WDS. Repair the malfunctioning part using the verified DTCs. For details, refer to "ON-BOARD DIAGNOSTIC SYSTEM (IMMOBILIZER SYSTEM) MALFUNCTION DIAGNOSIS FUNCTION".

• The immobilizer system cannot be deactivated.

• The immobilizer system must be reset using the WDS after performing any of the following: "Replacement of all the keys (steering lock replacement or similar procedure)", "Keyless unit replacement", "PCM replacement" and "Keyless unit and PCM replacement". Moreover, when performing "Replacement of all the keys" or "Keyless unit replacement", two or more keys usable with the immobilizer system must be readied. For details, refer to "IMMOBILIZER SYSTEM COMPONENT REPLACEMENT/KEY ADDITION AND CLEARING OUTLINE".
• Two or more key ID numbers must be registered for the engine to start. For key ID number registration, refer to the Mazda RX-8 Workshop Manual (1796-1*-03D) Section 09-14, "IMMOBILIZER SYSTEM COMPONENT REPLACEMENT/KEY ADDITION AND CLEARING".
• A maximum of eight key ID numbers can be registered for one vehicle. The PID/data monitor function can be used to verify the number of key ID numbers registered for a single vehicle. For details refer to "ON-BOARD DIAGNOSTIC SYSTEM (IMMOBILIZER SYSTEM) PID/DATA MONITOR FUNCTION".
• The following conditions may cause poor signal communication between the key and vehicle, resulting in the engine not starting or a key registration error. Do not perform key registration under the following conditions:
– If any of the following items are touching or near the key head.
• Spare keys
• Keys for other vehicles equipped with an immobilizer system
• Any metallic object
• Any electronic device, or any credit or other cards with magnetic strips