How to Program Your Key Fob

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How to Program Your Key Fob

The key fob is a truly convenient invention in the recent history of car parts and accessories. At one time, it was simply assumed that physically placing a car key into the car lock was the only way to unlock a car door. However, with the advent of remote keyless entry, drivers can now open their car doors with a push of a button. While most cars that are sold today come with a key fob standard, there are a few reasons that you may need to program a key fob in order to have it function properly over the course of a vehicle's life.

Programming a key fob can be done by a dealership, but it is also possible to do it yourself. Although the exact programming instructions will depend on the car's make and model, this guide will review some basic instructions that may be useful. Should you ever need to purchase a replacement key fob, that can be done at a local car dealership or even online from eBay Motors.

Key Fob Definition

There are a few different ways that people use the term "key fob." In some instances, this phrase refers to a type of keychain that is easily attached to a purse or carried in a pocket. Adding a key fob to a key makes that key easier to find and grab when it needs to be used. Although some people believe the word "fob" originates from the German for "pocket," this is not universally accepted.

For the purposes of this guide, key fob refers to the remote keyless entry device that comes standard on most modern cars. Like the keychain, they are meant to be attached to a key and do make it easier to grab, although that is not their chief purpose. Instead, this type of key fob allows you to unlock and lock a car, and in some cases open the trunk or deactivate the car's alarm system, from a short distance away and without engaging with the physical car key.

How a Key Fob Works

A key fob communicates with the locks in your car using radio wave signals. Both the key fob on your keychain and the car have memory chips that allow the fob to work. When the button is pressed on the fob, it sends a code to the car with the instructions as to what the car should do, whether that is to lock the car doors, unlock the car doors, or open the trunk. If the code sent to the car matches the code the car expects, it will perform that action. The code is randomly generated each time the fob is used. Programming the key fob is essentially making sure that the car and the fob are synchronized so that the car recognizes the codes the fob is sending.

Unprogramming a Key Fob

As previously mentioned, the key fob that is sold with a car will more than likely already be programmed to be used with that car. In many instances, this key fob will never need to be reprogrammed or replaced, even for the entire lifespan of the car. However, there are some reasons that a key fob may need reprogramming.

Lost or Destroyed Key Fobs

If a key fob is lost or otherwise destroyed, it may need to be replaced. In most cases, it is possible to purchase a new key fob from a dealership, but that may be an expensive endeavor. In order to save money, some people choose buy blank key fobs, which are not branded nor programmed to the car. These key fobs will need to be synced to your car before they can work.

Unprogrammed Key Fobs

Even if a key fob is not lost or destroyed, it may simply become unprogrammed. This can happen due to an error with the fob itself, or because of something the user did. For example, some key fobs are set so that if the button is pressed more than 256 times while it is out of range of the car; it will become out of sync and will need to be reprogrammed. Luckily, there are ways to fix this by programming the key fob.

Reprogramming a Key Fob

The exact steps for programming a particular key fob will depend on the make and model of the car, and may even differ for that model from year to year. The best bet for finding the exact instructions for reprogramming your key fob is to consult the owner's manual of the car. However, there are some steps that are fairly common, which may be of some use in the instance that a key fob becomes unsynchronized.

Basic Key Fob Programming Instructions

In most cases, you will need to be inside the car in order to program your key fob. It makes sense that this would be the case, since the ability to reprogram a key fob from outside the car would pose a major security issue.

Once inside the car, insert the key into the ignition and turn the ignition to the "on" position, but do not start the engine. In some cars, you will need to do this action a few times in a row in order to enter "program" mode. Once the car is in program mode, which may be indicated by a flash of lights or other indicator, simply press a button on the fob that needs to be programmed. This will sync the fob with the car. Then, you can switch the ignition to "off" and exit the car. The fob should now function properly and be able to lock the car remotely.

Special Considerations

If a car has more than one key fob, either for multiple drivers or as backups, it is a good idea to program all the fobs at once. If you do not do this, the fobs that are not synced at that time will most likely stop working. In some instances, you will actually need a fob that is already programmed correctly in order to sync another fob. In this case, if there is only one fob available, it may be necessary to visit a dealership for their expertise.

Replacement Key Fobs

As previously mentioned, a key fob may become lost or destroyed at one time or another. In this case, it is possible to buy "blank" or unprogrammed key fobs that can function as replacements. In some cases, these replacement fobs may even come with greater functionality than the standard vehicle's key fob. For example, an aftermarket car alarm system may come with its own key fob so that the system can be disarmed remotely before entering the car.

How to Buy a Key Fob on eBay Motors

Should the occasion arise that you do need to buy a replacement key fob, there are many options available on eBay Motors. By shopping on eBay Motors, you can browse through items from thousands of sellers around the world and find exactly the right key fob for you and your car.

In order to find the key fob that you need, enter your search terms in the search box on any page. You can enter "key fob" to get the most results, or something more specific like "GM key fob." On the results page, you will be able to sort the available items even further by using descriptors like price and condition.

Personal Seller Communication

One of the perks of purchasing on eBay Motors is that you can communicate directly with the seller of the item before you complete your transaction. For instance, if the item's description is unclear about the models with which the key fob is compatible, you can ask the seller directly, using the eBay interface. Once your question has been answered sufficiently, you can make your purchase with confidence.


The remote keyless entry key fob is a modern convenience that is often overlooked or even forgotten. However, when you are approaching the car with arms full of groceries or hands full of shopping bags, there is perhaps nothing that is a bigger relief than knowing it is possible to open the trunk with just the push of a button. People have come to rely so heavily on their key fobs that when one goes missing or stops working, it can be extremely frustrating. When this happens, it is important to remember that you can most likely program your key fob, or a replacement fob, to work again.

In fact, the process of programming your key fob is fairly simple. Once you find the instructions for your particular car, the actual programming should take only moments. Of course, if a key fob is completely lost or else destroyed, the first step will be finding a replacement key fob that is compatible with your car. This is easily done at a dealership or on eBay Motors. With the right key fob, programming is just a matter of following instructions and you will once again be able to access your car with ease.

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