Key Fob Programming – 7 Easy Steps for Reprograming

A remote keyless entry system is a type of electronic locking system used in modern vehicles to control access to the car. As its name implies, the system uses a handheld device to lock or unlock vehicle doors. Keyless entry systems may use traditional fob remotes or advanced Smart Keys.

What is remote keyless entry system and do I need Key Fob Programming?

Key fobs, also known as keyless entry remotes, are useful in controlling your car’s locks, trunk, panic alarm and even remote starter from hundreds of feet away.

Vehicle security has come a long way over the years. Early vehicles used mechanical locks and key combinations to unlock car doors. These days, modern vehicles come equipped with sophisticated locking systems that are more secure than their predecessor. While the auto industry is heading towards keyless entry systems, mechanical door locks are still widely used.

As with other mechanical locks, traditional car locks can be lock picked. On the other hand, keyless entry locks are harder to break since the locks are electronic and secured with codes that are hard to crack.

A more advanced form of keyless entry key allows the car owner to open the car doors and start the engine without physically pressing a button or inserting a mechanical key. These so-called “smart keys” rely wholly on sensors to unlock doors and start the ignition. However, smart keys still use mechanical keys as a backup.

How does the keyfob security system work

key fob programming

The keyfob system affects two aspects of vehicle security: vehicle entry and ignition. The system uses transmitters, transceivers, or transponders. These devices communicate by emitting and receiving radio signals. When the onboard computer receives a signal from the receiver, it then sends out a signal to the actuators on the car doors to unlock or lock them.

All key fobs operate at a frequency between 300 and 400 MHz. To prevent other car owners from accessing your vehicle, keyfob signals must be unique. The keyless entry system uses “rolling” or “hopping” codes to generate this unique signal. Codes are changed every time the keyfob is used. Hence the name is rolling or hopping.

In addition to excluding other keyfobs, rolling codes deter thieves using code grabbing devices since the codes are refreshed each time the key fob is used. Keyfob codes are also encrypted, making it extremely hard for thieves to crack the signals.

Some key fobs come with engine immobilizers for added security. The system is designed to prevent the engine from being hot-wired by preventing fuel flow to the engine. Just like the keyless entry system, the engine immobilizer operates through radio signals and uses rolling codes that are refreshed each use.

Immobilizers provide extra security, especially when the mechanical key that came with the fob is duplicated. The duplicate key won’t be recognized by the vehicle even if it is an exact duplicate. The key fob must contain the code that the vehicle’s ignition system identifies for it to work.

The more advanced smart-key system operates just like keyless entry remotes. Smart keys use radio signals and rolling codes too. However, the difference is that intelligent keys use sensors to detect the proximity of the smart key (and the person holding it) to the vehicle. The smart-key system automatically unlocks the doors, disengages the immobilizer, and starts the ignition when it senses that the key is nearby.

What you need to reprogram when key fob programming comes in question (software, tools, etc.)

Fob replacement is not as straightforward as replacing your TV remote. The keyfob needs to be reprogrammed in order for the onboard computer to recognize the new fob. You may also have to program new fobs you intend as spares.

Reprogramming your keyfob can be done manually or by using programming devices. Most modern vehicles have built-in keyfob programming features. The programming procedure may vary from model to model, but the crucial steps are the same. Basically, the car is manually set to programming mode to recognize the fob to be programmed.

Key Fobs can also be reprogrammed using dedicated key programming devices or software applications. (Provide device and software examples)

How do you reprogram remote key fobs?

Before programming your remote key, make sure that its battery has sufficient charge to power the device. To program remote keyfobs without immobilizers, follow the following steps:

Step 1: Get inside your vehicle and lock the doors.

Step 2: Make sure that the door locks are engaged not to disrupt the reprogramming process.

Step 3: Insert your car key into the ignition switch and turn the ignition to the “ON” position.

Step 4: While the key is in the “ON” position, press the “Lock” button on the keyfob.

Step 5:Turn the key back to the “OFF” position.

Step 6: Repeat steps 3, 4, and 5 in quick succession, at least four times until you can hear the lock cycle.

Step 7: Test the reprogrammed fob if it’s working.

Step 8: If all checks out, congratulations! You’ve successfully programmed your fob.

How do you reprogram smart key fobs with immobilizers?

Reprogramming smart fobs with immobilizers is more difficult than the standard keyless entry fobs. This is so because the immobilizer system has its own security code. This is also true when programming fobs with duplicate mechanical keys.

Before programming your duplicate key fob, make sure that the key’s blank blade is machined to match the profile of the original key. To program smart keys, follow the following steps:

Step 1: Insert the unprogrammed duplicate key into the ignition switch,

Step 2: Connect your programming device to the OBD2 port of your vehicle.

Step 3: Run the programming software compatible with your vehicle and your programming device. (See example above)

Step 4: Carefully follow the instructions prompted by your programming device.

Step 5: Wait for the programming device to program your fob with a new code.

Step 6: Check if the key is recognized by your vehicle by starting the ignition.

Step 7: If everything is in order, you’ve successfully programmed your key.


Does AutoZone program key fobs?

Technically, no. AutoZone does not offer reprogramming services per se. However, the automotive retailer sells replacement keyfobs, and you could ask their salesperson to assist you in reprogramming your new fob.

How much does it cost to program a key fob?

Fob reprogramming typically costs between $50 to $100. It can even go as high as $500 for more advanced fobs. Expect to shell out upwards of $200 in the dealership if you need a key replacement to go along with your newly programmed keyfob. Certified locksmiths usually charge around $25 less than the dealership.

Do aftermarket key fobs work?

Yes. Aftermarket key fobs work on almost any vehicle provided that they are compatible with your vehicle. Before buying a replacement or a spare fob, always check your old fob’s model number to ensure compatibility.

Can any key fob work in any car?

No. Key fob signals are changed every time the fob is used to exclude other fobs and discourage thieves. Also, the signals are encrypted for added security.

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