Why Can't the Spare Mechanical Key Start the Engine?

[MacTessa]

Spare mechanical key cannot start the engine because the vehicle is equipped with an engine immobilizer system. The engine will only start when the system recognizes that the chip inside the key matches the code stored in the immobilizer system. Since the spare key does not contain a chip, it cannot start the vehicle and can only be used to unlock the doors when the primary key is lost. There are some differences between the spare key and the primary key, although most functions are the same. The main differences between the primary key and the secondary key are: the teeth of the primary key and the secondary key are slightly different, the primary key can open the trunk, while the secondary key cannot. If the key is lost and only the primary key remains, you can directly add another primary key. If only the secondary key remains, you need to replace the certified ECU and all the lock cylinders in the vehicle.