immobilizer playing up, after replacing a lost key it will start/not start intermittently?

2002 MAZDA 323
250,000 MILES • 1.8L • 4 CYL • 2WD • AUTOMATIC
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DAZUR72
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lost the key had new one coded but sometimes it starts sometimes it doesn't. its light flashes three times it might go off car will start, or it stays on car will not start now and then light will go off. car won't start. Any help is much appreciated.
Oct 22, 2024 at 1:39 PM
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STRAILER
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Sure if the security light is flashing and the car will not start the security system is enabled. You can try disconnecting the battery overnight, which should reset the system. If this works and then stops working and the security light continues to flash the key, you had made is not working correctly or the IR reader needs to be replaced. Here is how the job is done and here is a trouble tree for you to go over.
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Oct 22, 2024 at 5:31 PM
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