Transponder Keys: What makes them effective for your vehicle's safety and security?


Transponder systems are factory-installed anti-theft systems. Motorcycles as well as cars and trucks are coming equipped with immobilizer systems and transponder keys.


The transponder / ignition key provide convenience as well as a degree of security and safety. Most post-1995-built vehicles have transponder chips and built-in immobilizer systems. Each key has a transmitter inserted in the head of the key. Typically a device is placed behind the steering wheel and locks or unlocks the vehicle when it recognizes the transmitted signal from the key's chip. When the key is inserted the engine control unit (ECU) (aka computer under the hood) sends and receives a message that allows the car to start. As a result, it is extremely important that keys are exactly cut and programmed to fit the locks and disarm the immobilizer.

Safety Factor

Immobilizer systems are virtually impenetrable and theft is negligible. Only the device that is programmed to respond will recognize the transponder key's pre-determined frequency and alphanumeric code.

Vehicle transponder keys are useful as safety and security devices because:

Keyless remote entry systems are designed with digital identity codes initially programmed by the car manufacturer. The operator typically puts the vehicle in “programming mode” by engaging a lever that activates the fob button which sends the digital identity code to the vehicle's computer. Once the code is saved, the vehicle is out of programming mode and starts.

On Board Programming

A locksmith is required to duplicate keys since most transponder keys must be programmed to fit the particular vehicle. Or they may be cloned from the vehicle's existing key. Some vehicles do not need special equipment to program keys to fit them. New security codes can be introduced to the vehicle's computer to accommodate on board programming when necessary.

The vehicle's owner or locksmith can, in some cases, program their own keys using On Board Programming (OBP). On Board Programming works if:

It is advisable to contact a locksmith to be sure you have the correct type of key: Zero bitted type or encrypted type.

Newer transponder systems' encryption has a rolling code where the ID and password change each time the key is used. The caution is that some (older) transponder-based immobilizer systems remember the last key code longer than it should. This makes it possible for the system to accept a non-transponder key and enable the system even after removing the original key.

For more information contact Randburg Locksmiths today!