Transponder keys are devices used to transmit radio signal to a receiver from a handheld device. They are typically used to start and unlock vehicles. Beside cars, these are also used for keyless entry systems and gate openers. Each transponder car key is programmed to start only a specific vehicle, thus reducing possibility of theft.
How a Transponder Works
A transponder is actually short for transmitter and responder. This was invented in 1944 and is simply a miniature electronic chip that has non-volatile memory. This is a type of memory that does not require constant energy. Along with the chip are windings or fine wires coiled around a tube. The transponder type used for automobiles is the magnetic coupled transponder system, which is passive in nature, meaning it does not require constant electricity. Transponder systems may also be either fixed or rolling code. Fixed code type features a transponder that is energized and sends a fixed code onto the security module, while rolling codes use different codes that a vehicle knows for it has been calculated in its memory.
Vehicular transponder keys were first used in 1995, with a transmitter unit consisting of a small microchip in the key’s plastic part. This chip has a serial number set during programming. The chip sends request to the vehicle for such serial number to be validated, turning off engine immobilizer to be able to start or unlock the car. Hence, if the number is not recognized, the car remains locked or immobile. A key can still turn engine over even if it has not been programmed, however, it will not be able to start the car because immobilizers are still activated.
Transponder keys for cars are available for different vehicles, though they are more common in newer models. Cars can be retrofitted with transponder systems by a car locksmith, but it could be expensive since it would involve reprogramming of electrical system. It is wise to keep two of these keys because key replacement is expensive. Other problems with transponder keys you might encounter are when they start malfunctioning. This might be just due to low battery inside the transponder. However, if the chip is damaged for some reason, you need help from a professional.
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