Immobilizer System Component Replacement/Key Addition And Clearing [Keyless Entry System]: Foreword

• The immobilizer resetting procedure using the M-MDS must also always be performed when performing the following procedure: "instrument cluster replacement", "PCM replacement", "instrument cluster and PCM joint replacement", and "key ID number clearing". The engine will not start unless all work is performed using the M-MDS.
• For adding a key, there are two ways, either using the M-MDS or using two keys with which the engine can be started.
• When replacing any of the immobilizer system component parts, adding/clearing keys, or performing other functions, refer to the following table and perform the applicable procedure (No.1 to 7) .

IMMOBILIZER SYSTEM COMPONENT REPLACEMENT REFERENCE

Reference number	Situation	Required items	Cautionary notes
1	Have two or more keys with which the engine can be started, and making a spare key, or programming an additional key. (See NO.1 ADDITIONAL KEY REGISTRATION PROCEDURE (USING TWO VALID KEYS) .)	Registration key	The M-MDS is necessary for the additional key programming if gCustomer Spare Key Programming Disable h is set before the procedure using the M-MDS. In this case, perform No.2.
2	If there is only one key that can start the engine, make a spare key. If there is no key, program an additional key. (See NO.2 ADDITIONAL KEY REGISTRATION PROCEDURE (USING THE M-MDS) .)	Registration key M-MDS	-
3	Clearing the programmed key ID number. (See NO.3 Key Replacement Procedure (Clearing Previously Programmed Key ID Numbers, Key Re-program) .)	Registration keys (Two or more) M-MDS	All the key ID numbers programmed to the vehicle will be cleared. Unless keys are reprogrammed after the procedure, the engine cannot be started. Before beginning the procedure, verify that the customer has turned in all of the keys for the vehicle. Two or more keys need to be programmed after the procedure to start the engine. The keys (two or more) to prepare for the procedure do not have to be new ones; there is no problem with using the keys with which the engine can be started.
3	Replace all the keys. (Steering lock replacement or similar procedure) (See NO.3 KEY REPLACEMENT PROCEDURE (CLEARING PREVIOUSLY PROGRAMMED KEY ID NUMBERS, KEY RE-PROGRAM) .)	New keys (two or more) M-MDS	The previous keys will be invalid since the steering lock is replaced. Have two or more new keys ready for programming before beginning the procedure. Unless keys are reprogrammed after the procedure, the engine cannot be started.
4	Changing the additional key programming procedure. (Method for programming other keys using two keys that can start the engine is disabled.) (See NO.4 ADDITIONAL KEY PROGRAMMING PROCEDURE CHANGING .)	M-MDS	The additional key programming using No.1 cannot be performed after the procedure. It is possible to restore the setting. For restoring the setting, the M-MDS or equivalent is necessary.
4	Changing the additional key programming procedure. (Allows programming using two keys that can start the engine.) (See NO.4 ADDITIONAL KEY PROGRAMMING PROCEDURE CHANGING .)	M-MDS	New vehicles have this setting.
5	Replacing the instrument cluster only. (See NO.5 RESETTING PROCEDURE FOR THE IMMOBILIZER SYSTEM WHEN REPLACING THE INSTRUMENT CLUSTER REPLACEMENT .)	New instrument cluster Registration keys (two or more) M-MDS	Unless keys are reprogrammed after the procedure, the engine cannot be started. Before beginning the procedure, verify that the customer has turned in all of the keys for the vehicle. Two or more keys need to be programmed after the procedure to start the engine. The keys (two or more) to prepare for the procedure do not have to be new ones; there is no problem with using the keys with which the engine can be started.
6	Replacing the PCM only. (See NO.6 RESETTING PROCEDURE FOR THE IMMOBILIZER SYSTEM WHEN REPLACING THE PCM .)	Replacement PCM M-MDS	-
7	Replacing the PCM and instrument cluster at the same time. (See PROCEDURE .)	New PCM New instrument cluster Registration keys (two or more) M-MDS	Unless keys are reprogrammed after the procedure, the engine cannot be started. Before beginning the procedure, verify that the customer has turned in all of the keys for the vehicle. Two or more keys need to be programmed after the procedure to start the engine. The keys (two or more) to prepare for the procedure do not have to be new ones; there is no problem with using the keys with which the engine can be started.
-	Replacing the coil antenna.	New coil antenna	Immobilizer system resetting is not necessary.

CAUTION:

• If any of the following items are touching or near the key head, signal communication between the key and vehicle is negatively affected, resulting in the engine not starting or the key registration failure. Do not perform the procedure if any of the following items are touching or near the key head.
  • Any metallic object
  • Spare keys or keys for other vehicles equipped with an immobilizer system
  • Any electronic device, or any credit or other cards with magnetic strips

NOTE:

• Within the following procedures, the term a "valid key" means a "key that can start the engine".
• After adding/registering keys, clearing ID numbers or replacing any component part of the immobilizer system, verify that all keys can start the engine within 5 s. 
• When verifying that the keys can start the engine, wait at least 5 s or more  between inserting them.
• If the engine cannot be started using a registered key, repeat the procedure from the beginning.
• Do not start the engine until the key registration procedure for all the necessary keys is completed. If the engine is started during the registration procedure, registration is stopped at that point. Repeat the procedure starting from the beginning if the engine is started before completion.
• Two or more key ID numbers must be registered for the engine to start.
• A maximum of eight key ID numbers can be registered for one vehicle. The M-MDS can be used to verify the number of key ID numbers registered to a single vehicle.
• Do not select screen menus of the M-MDS that are not indicated within the procedures.

Fig 1: Precaution For Touching Key Head To Metallic Object

Courtesy of MAZDA MOTORS CORP.