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

WARNING: This page is about a different car, the 2007 Mazda MX-5 Miata. However, it is still accessible from the selected car via links, so may be relevant.

When performing the following procedures, the immobilizer resetting procedure using the M-MDS must also always be performed: "instrument cluster replacement", "PCM replacement", "instrument cluster and PCM joint replacement", "Key ID number clearing". The engine will not start unless all work is performed using the M-MDS.
There are two methods for registering an additional key: Using the M-MDS and using two keys that are able to start the engine.
When replacing any of the immobilizer system component parts, adding/erasing keys or performing other functions, refer to the following table and perform the applicable procedure (No.1 to 5).

IMMOBILIZER SYSTEM COMPONENT REPLACEMENT/KEY ADDITION AND CLEARING PROCEDURE [KEYLESS ENTRY SYSTEM]

Reference number	Situation	Required items	Cautionary notes
1	Making a spare key when the customer has two or more keys that can start the engine. Or registering an additional key.	Registration key	If the additional key registration method has been changed to "Customer spare key programming disabled" (inhibiting the method that uses two keys that are able to start the engine), the M-MDS is required when registering the additional key. In that case, perform procedure No.2
2	Making a spare key when the customer has one key that can start the engine or no keys. Or registering an additional key.	Registration key M-MDS	-
3	Clearing previously registered key ID numbers.	Registration keys (two or more) M-MDS	All the key ID numbers registered in the vehicle will be 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 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.
3	Replace all the keys. (Key cylinder replacement)	Registration keys (two or more) M-MDS	When replacing the key cylinder, have two or more keys ready for registration before beginning the procedure, since the previous keys will be invalid.
4	Changing the method for registering additional keys. (Method for registering other keys using two keys that can start the engine is disabled.)	M-MDS	After performing this procedure it is not possible to register additional keys according to procedure No.1. The system can be returned to the original setting. The M-MDS must always be used to change the system setting.
4	Changing the method for registering additional keys. (Method for registering other keys using two keys that can start the engine is enabled.)	M-MDS	This is the default setting on new vehicles.
5	Replacing the instrument cluster.	Replacement instrument cluster Registration keys (two or more) M-MDS	Unless keys are registered after replacing the steering lock, 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.
5	Replacing the PCM.	Replacement PCM M-MDS	-
5	Replacing the PCM and instrument cluster.	Replacement PCM Replacement instrument cluster Registration keys (two or more) M-MDS	Unless keys are registered after replacing the steering lock, 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 antenna.	New coil antenna	It is not necessary to reset the immobilizer system.

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: Caution For Key Registration Failure
Courtesy of MAZDA MOTORS CORP.