How to Sync a Key Fob: Types, Common Problems, and More

Some car models let you program numerous key fobs to the unit. For example, a Ford Focus can have eight fobs synced into the vehicle. This lets you keep different spare keys if you lose the main one or if it malfunctions.

Whether you have one or multiple key fobs, note that they’ll only work if they’re properly synched or programmed to the vehicle.

Syncing or Programming Key Fob

Syncing or programming a key fob differs depending on your vehicle’s make and model. However, the instructions for syncing are generally similar. They usually involve the following steps:

• Step 1: Get all the key fobs you want to program, as well as existing ones. You’ll need to program them all in case the vehicle erases their data.
• Step 2: Enter the vehicle and close the door. Insert the key into the ignition without turning the engine on.
• Step 3: Turn the key to the on position without starting the engine and back to off. Check your owner’s manual or consult with the manufacturer to see how often you need to do this within a certain time frame.
• Step 4: If done properly, the car would enter programming mode, which is indicated by door locks locking and unlocking or an audible sound.
• Step 5: Press any button on the key fob you want to program. If successful, the car would cycle the door lock, flash the lights, or emit a chime.
• Step 6: Repeat the previous steps for the other fobs you want to sync.
• Step 7: Start the engine, turn it off, and test all the key fobs you programmed to ensure they work properly.

Types of Keyless Entry Remote Programming

There are several ways to program a key fob, including the one listed above called self-programming. They include dealer programming, onboard programming, key fob cloning, OBD2 programming, and on-bench programming.

Dealer Programming

As the name suggests, this type of programming is done by a dealership. Dealerships have specialized diagnostic tools to program a new fob to the car.

For dealer programming, you might have to pay a fee of somewhere between $50 and $250, depending on factors like vehicle model and fob type.

Onboard Programming

Onboard programming pairs a key fob using your vehicle’s infotainment system or dashboard. The process differs per brand and model, but generally, it involves navigating the menus, typing in a security code, and following the instructions.

Key Fob Cloning

Some locksmiths can duplicate key fobs equipped with the same identification code and encryption so they’ll work with your vehicle. The price of duplicating a key fob varies, but expect to pay over $100.

OBD2 Programming

This type of programming requires OBD2 protocols to modify the data to program a key fob to the car. Everything is done through the OBD (on-board diagnostics) and a highly advanced car key programmer, meaning not everyone can sync a key fob designed this way.

The assistance of an auto locksmith might be necessary, as they’ll have the required tools to program this type of key fob. You’ll usually encounter this programming type on newer vehicles.

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On-Bench Programming

On-bench, or EEPROM, programming requires extracting modules out of the car so it can read the correct password and stored key data inside the fob microchip. This allows you to enter programming mode and sync the new key to the car.

If done incorrectly, this type of programming can corrupt the information on the module, which is why it’s best to let an expert do it. The EEPROM method is usually only done when there are no options to bypass the anti-theft system.

Common Problems With Key Fobs

If your key fob isn’t working even after syncing, then it might have other issues. Some possible ones include unresponsive buttons, weak signals, electronic interference, programming issues, and a dead battery.

Unresponsive Buttons

Unresponsive buttons are one of the most common issues key fobs face, usually due to worn-out buttons or a dead battery. If replacing the battery doesn’t fix it, you might need to replace the fob itself.

Weak Signals

Weak signal is another common issue, but it depends on variables like proximity between the fob and the car. It makes it difficult to unlock or start a car, especially in parking lots. Installing a signal booster or range extender can improve the fob’s signal strength.

Electronic Interference

A possible reason for weak signals is interference from other electronic devices. Smartphones, Wi-Fi routers, and other key fobs can mess with the signal and result in communication errors that prevent you from unlocking your vehicle.

Moving away from other devices will help prevent or resolve this issue. If that doesn’t work, try to stay clear of metallic objects because they can also mess with the fob’s signals.

Programming Issues

Programming issues are also possible due to software glitches or changes in the vehicle’s settings. It’s one of the reasons for syncing a key fob, alongside getting a new fob.

Luckily, the solution is pretty simple, as you only need to reprogram the fob by consulting your owner’s manual or visiting a dealership/auto locksmith.

Dead Battery

Lastly, a dead battery is one of the most common key fob problems. There are different signs of a dead fob battery, including a malfunctioning LED light, needing multiple clicks to work, and delays in locking/unlocking.

How to Change Key Fob Battery

To change a key fob battery, follow the steps below:

• Step 1: Depending on the key fob, you may have to remove the key first by sliding it out or pressing a button to swing it to the top of the fob.
• Step 2: Unscrew the back of the fob if it has a screw. If your fob has a seam, use a coin or a screwdriver to separate the fob. If both aren’t present, use a flat screwdriver at any point on the seam and lift to separate the fob.
• Step 3: Lift the old battery out using a screwdriver.
• Step 4: Place the new battery in the same position as the old one.
• Step 5: Press the two halves back together.

Step 6: Test the key fob to see if it works.