• Always use the M-MDS or equivalent to verify DTCs even if the security light displays a DTC. If the security light itself has a malfunction, it is possible that a DTC may not be properly displayed. There are certain DTCs which can only be verified using the M-MDS, not the security light.
• DTCs for the immobilizer system that are stored in the keyless unit and PCM are cleared when the ignition switch is turned from the ON to the LOCK (or ACC) position.
• If DTCs are not displayed even though the engine does not start or stalls, perform the following symptom troubleshooting:
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• The following conditions may cause poor signal communication between the key and vehicle, resulting in the engine not starting or a key registration error. Do not perform any work under the following conditions:
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― If any of the following items are touching or near the key head.
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• Spare keys
• Keys for other vehicles equipped with an immobilizer system
• Any metallic object
• Any electronic device, or any credit or other cards with magnetic strips