IMMOBILIZER SYSTEM CONSTRUCTION/OPERATION

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•  The immobilizer system consists of the key (built-in transponder), coil antenna, keyless control module, PCM, and the security light (in instrument cluster).
•  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 cannot be disabled.
•  The engine cannot be started without a previously programmed key.
Caution
•  If a metallic or magnetic object is near the key, communication between the key and the vehicle may be obstructed resulting in the inability to start the engine.
•  It is also possible that due to other malfunction causes in other systems (such as engine, starter relay) the engine may not start even though the immobilizer system is operating normally. If the immobilizer system is malfunctioning, the security light displays the DTC. The displayed DTC is recorded in the keyless control module and the PCM.

Engine Start Operation

•  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 approx. 0.1 s every 2 s.
•  The order of operation for enabling engine starting is as follows:
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•  If any of the following services is performed, reprogramming of the immobilizer system using the Mazda Modular Diagnostic System (M-MDS) is necessary for proper immobilizer operation.
Caution
•  The engine cannot be started unless reprogramming is performed using the Mazda Modular Diagnostic System (M-MDS).

Situation

Items neccesary to perform procedure (always have these ready before beginning the procedure)

Cautionary notes
Making a spare key when the customer has two or more keys that can start the engine. Or registering an additional key.
•  Keys for registration
•  If “Customer Spare Key Programming Disable” has previously been performed using the Mazda Modular Diagnostic System (M-MDS), the Mazda Modular Diagnostic System (M-MDS) must be used to register an additional key.
Making a spare key when the customer has one key that can start the engine or no keys. Or registering an additional key.
•  Keys for registration
•  Mazda Modular Diagnostic System (M-MDS)
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Clearing previously registered key ID numbers.
•  Keys for registration (two or more keys)
•  Mazda Modular Diagnostic System (M-MDS)
•  All key ID numbers registered in the vehicle are cleared.
•  Unless keys are re-registered after clearing the key ID numbers, the engine cannot be started. Before beginning the procedure, verify that the customer has turned in all of the keys for the vehicle.
•  Unless two or more keys are registered after clearing the key ID numbers, the engine cannot be started.
•  The keys (two or more keys) readied before beginning the procedure do not have to be new keys. Any key that is capable of starting the engine before beginning the procedure can be used.
Replacing all keys. (When replacing the steering lock or similar procedure)
•  New keys (two or more keys)
•  Mazda Modular Diagnostic System (M-MDS)
•  Since the steering lock is replaced, keys used before replacement become unusable. Have two new keys or more ready before beginning the procedure.
•  Unless keys are registered after replacing the steering lock, the engine cannot be started.
Changing the method for registering additional keys. (Method for registering other keys using two keys that can start the engine is disabled.)
•  Mazda Modular Diagnostic System (M-MDS)
•  After performing this procedure, additional keys can only be registered using the Mazda Modular Diagnostic System (M-MDS).
•  The setting can be changed to the original using the Mazda Modular Diagnostic System (M-MDS).
Changing the method for registering additional keys. (Method for registering other keys using two keys that can start the engine is enabled.)
•  Mazda Modular Diagnostic System (M-MDS)
•  This is the default setting on new vehicles.
Replacing the keyless control module only.
•  New keyless control module
•  Keys for registration (two or more keys)
•  Mazda Modular Diagnostic System (M-MDS)
•  Unless keys are re-registered after replacement, the engine cannot be started. Before beginning the procedure, verify that the customer has turned in all of the keys for the vehicle.
•  Unless two or more keys are registered after replacement, the engine cannot be started.
•  The keys (two or more keys) readied before beginning the procedure do not have to be new keys. Any key that is capable of starting the engine before beginning the procedure can be used.
Replacing the PCM only.
•  New PCM
•  Mazda Modular Diagnostic System (M-MDS)
-
Replacing the PCM and keyless control module.
•  New PCM
•  New keyless control module
•  Keys for registration (two or more keys)
•  Mazda Modular Diagnostic System (M-MDS)
•  Unless keys are re-registered after replacement, the engine cannot be started. Before beginning the procedure, verify that the customer has turned in all of the keys for the vehicle.
•  Unless two or more keys are registered after replacement, the engine cannot be started.
•  The keys (two or more keys) readied before beginning the procedure do not have to be new keys. Any key that is capable of starting the engine before beginning the procedure can be used.
Replacing the coil.
•  New coil
•  It is not neccessary to reset the immobilizer system.
Replacing the instrument cluster.
•  New instrument cluster
•  It is not neccessary to reset the immobilizer system.