Immobilizer System Service Caution

CAUTION:

When an immobilizer system component (such as the PCM, immobilizer unit, coil or the key) has failed, it must be accurately determined according to the troubleshooting procedures or by the display of the DTCs prior to carrying out the service procedures.
If a normal component is mistakenly replaced and the ID number and/or code word are input into the new component, then neither component can be reused on other vehicles.
When a new key registration or immobilizer unit and/or PCM replacement is performed on vehicles equipped with an immobilizer system, the new ID number should be registered using the procedure that includes engine cranking through idling. When the engine starts to reprogram the immobilizer system, if the input voltage to the immobilizer unit becomes lower than the operation voltage of the immobilizer system, the ID number can not be input momentarily. This is not a unit failure, so do not misunderstand during the problem diagnosis (when the terminal voltage goes back to the operation voltage, then the unit also begins to operate normally). Charge or replace the battery.

NOTE:

When an error occurs during the reprogram procedures, except when both the immobilizer unit and PCM are replaced, repeat the procedure from Step 1) of procedure being performed. If you still cannot reprogram, confirm how many keys can start the engine. Then, perform the key replacement or addition reprogram procedure according to the valid key number.
To make a copy of the key or replace the immobilizer system component parts (the key(s), steering lock, immobilizer unit and/or PCM), the customer should bring all keys to the dealer. This is because the previously programmed key IDs are erased when reprogramming the key IDs into the immobilizer unit and PCM.
If the customer has only one valid key when replacing the immobilizer system component parts, the dealer should contact a distributor to obtain the code word.
To replace the immobilizer unit to PCM, there should be at least one valid key. Otherwise, both the immobilizer unit and PCM should be replaced.
The immobilizer unit and PCM cannot be changed from one car to another. If an immobilizer unit or PCM is replaced with one from another car, the engine will not start. Reprogramming of the IDs and code word of an immobilizer unit that has already been programmed as set is not possible.
The immobilizer unit and PCM should not be newly replaced as a trial during troubleshooting. If this is done, the ID and code word will be programmed into the new unit and it cannot be used for other cars even if you find that the old unit was normal.
The immobilizer system cannot be deactivated.
Confirm that all keys registered can start the engine after the reprogram procedure. When confirming, wait for more than 5 seconds before inserting the next key.
When the customer does not need to register more than two keys, the following procedures can be stopped after registering two keys.