Encrypted Code Registration Method
Required Special Tool: MB991502: Scan Tool (MUT-II)
If the ignition key, Immobilizer-ECU, ECM (M/T) or PCM (A/T) is replaced or an ignition key is added, encrypted codes of all the ignition keys must be registered. (A maximum of eight different ignition key can be registered.) Moreover, when the immobilizer-ECU has been replaced, you will need to use scan tool MB991502 to register the immobilizer-ECU and input the vehicle secret code and to register the password (secret code) that the owner specifies into the immobilizer-ECU.
If an attempt is made to start the engine with an unregistered ignition key, cranking occurs, but fuel supply is cut off to disable the engine. In about 10 seconds, the theft-alarm indicator will blink for about 30 seconds.