How Auto Locksmiths Program Key Fobs and Transponders

Modern car keys offer both convenience and security using transponder chips and remote key fobs. While they often come in a single unit, it's important to understand how each component functions and how auto locksmiths program them.

Key Fob VS Transponder

A key fob (or a smart key) is a small remote-controlled device which controls the remote keyless entry system for your car, providing a convenient and simple way of car security. Key fobs use radio-frequency identification (RFID) or near-field communication (NFC) technology, enabling you to unlock and access your car without the need for traditional keys. With just the push of a button, the key fob communicates with a unique tag associated with your car, letting it lock or unlock the vehicle.

A transponder is a small microchip within the key. Like a key fob, they use RFID to detect a digital serial number that matches up to the unique serial number within the key. Only with the unique serial number will the car lock or unlock. It also uses that microchip to communicate with the vehicle’s immobiliser system to start the engine; a key fob will often have the same transponder technology to authenticate with the immobiliser.

In many modern vehicles, the key fob includes both remote entry functions and a transponder chip, combining both technologies in one device.

Programming A Key Fob or Transponder

Auto locksmiths use specialized diagnostic tools to pair a new or replacement key with your vehicle. Here's how the process generally works:

1. They start by verifying specific details about the vehicle to select the correct blank key for programming.

2. The vehicle’s password is obtained through software and computers for programs like an OBD2 scanner or an EEPROM programmer via the car's OBD port (often under your dashboard).

3. A car diagnostic tool then interacts with the immobiliser system to reset it, enabling it to pair with a blank transponder or retrieve PIN codes. A blank transponder chip is used to ensure compatibility with the stored vehicle code.

If key programming is done incorrectly, it can lead to the key malfunctioning and may even damage the key or the car's immobiliser, resulting in costly repairs.

Our auto locksmiths can cut and reprogram a cloned key in approximately 2 to 30 minutes. If you're concerned about your key, consider having a spare key made. This can save you time and money in case your original key is ever lost or damaged.

Why Do Key Fobs and Transponder Break?

Common reasons your key fob or transponder might stop working include:

• Dead battery (for key fobs)

• Loss of connection between the key and the vehicle

• Water damage, corrosion, or internal circuit failure

• Wear and tear, especially if the key has been dropped

Transponder chip failures may result in:

• The engine turning over but not starting

• Warning lights on the dashboard

• An immobiliser or key symbol appearing on the display