Electronic car keys or key fobs provide convenience for unlocking and locking car doors, trunk access, alarm, and sometimes help with starting your car from a distance.
However, like all other electronic systems, they may eventually stop functioning as a result of data loss or signal loss. Fortunately, in most cases, it is relatively easy to program a key fob or to reprogram a key fob at home in order to relearn the data.
In this article, we explain in a step-by-step process how to program your car’s key fob yourself to avoid going to the car dealer and wasting your hard-earned money. Let’s get started!
What do you need to know about the key fob system?
In general, key fobs increase security in two ways: limiting access to a vehicle and starting. Previously, RF technology was used to limit access to a car, but the application was less than efficient due to easy programming and signal manipulation.
There was also an infrared system that worked like an RF system, whereby a security remote had to be pointed toward the vehicle to achieve its desired result.
Thankfully, today, fob locks are more advanced, and a unique code is generated from the fob and receiver built into the vehicle. Due to transponder and ECU technology, the key fob system is markedly better for security.
Lastly, you will have the option of both starting your car using the ignition key or the fob remote with this advanced technology. There are also high-tech and luxury cars that use these security codes to modify configurations to the owner’s preferences.
Generally, those features require a working automobile battery voltage. For example, the transponder technology uses code communications between the vehicle’s frequency receiver and the electrically coded key.
Generally, when you press the fob button, the radio frequency sends a unique code to engage a particular target vehicle function. Despite the complexity of the FOB operation, it is fairly straightforward to reprogram most types of key fobs.
How do you program a key fob?
It is important to keep in mind that different models of vehicles will have different styles and types of key fobs before going through the steps necessary to program fobs.
I have recently compiled an effective process for the most common key fobs on the market, and I thought to share the specific key fob programming steps.
Some key fobs will require a more complex process called reconfiguration, and that will likely require the help of a professional. However, if you want to attempt to do it, please follow these specific reconfiguration steps.
#1. Change the Key Fob Batteries.
Before doing anything else, please change the battery in the key fob if it has been some time since the last change. The last thing you want while reprogramming the fob is for a dead battery to give you a headache.
Batteries for key fobs are typically inexpensive and easy to change, so it is worth it to go through potential troubles. If you don’t know how to change them, please check your owner’s manual or a repair manual.
#2. Get into the vehicle.
To start, get into the driver’s seat of the vehicle using all of your key fobs and car keys, then proceed to close all the doors. It is essential to close the doors during this process – leaving just one door open can mess up the sequencing.
#3. Turn on to ignition.
After sitting in the vehicle, you wish to put the car key in the ignition and turn it on. The steering, electrical system, and electrical console are getting powered by turning the ignition switch to the “on” position. Make sure it is not in radio mode, and do not start the engine.
#4. Press the lock button on the key fob.
With the key turned to ‘On,’ press the lock button, and put it back to ‘Off.’ You need to repeat this process at least three times and end with the key in the ‘On’ position.
This sends a signal to the electronic control modules that there is a legitimate signal from that key, and it saves the data afterward.
#5. Listen for a lock sound.
After doing the above, listen for the lock sound, which unlocks the doors. This is an indication that the car is now in programming mode, and so far, the process is effective.
When you hear the door lock, press the lock button on your key fob again within 5 seconds, and programming should be successful.
#6. Program Additional Remotes.
If there are additional remotes you would like to program to your car, you must press the ‘Lock’ button within 10 seconds after getting into programming mode to program those remotes also.
You can also try to press the lock or unlock buttons at the same time as you program the primary remote when you turn the ignition on in the beginning to obtain a successful outcome.
#7. Turn Off the Ignition.
Once you have completed the above steps and received a successful signal for all the key fobs you wanted to program, turn the ignition back to the ‘Off’ position to terminate the programming process.
#8. Exit the vehicle and test the results.
Take all of the key fobs you programmed with you and exit the vehicle, closing all doors. Test the unlock and lock functions of all of the key fobs that have been programmed to verify functionality.
If the key fobs still do not work, or only one of the key fobs works that you attempted to program, you may want to try the entire process one more time. However, there is always the possibility that this method does not work on your vehicle model.
Specialist Hardware Necessary for key fob programming
For some vehicles, key fob programming may not be as easy as above and may require special hardware and software.
If you find yourself in one of those vehicles, generally, we recommend you check with your authorized car dealer to find out how to program a key fob for your particular car model.
Because getting your information or help from the authorized dealer may be expensive and not worth it for older car models, you can try a locksmith or a local auto repair shop.
Key Fob Programming and Immobilizer Systems
The information above is only for programming the key fobs to be able to unlock the doors to enter the vehicle.
If you also want to program new keys to be able to start the car engine, this is usually more difficult and not something you can do yourself at home without appropriate tools.
This is because all modern cars come with an immobilizer system. Even if you make a copy of the original key and program a key fob to match the new key, the engine will not start with that key without going through the programming procedure.
The car key has a small chip or transponder inside the key that sends a signal to the immobilizer system in your car. If the signal is incorrect, the engine control module will not let the engine start.
Therefore, you will have to program the immobilizer to match the transponder chip in the new car key. Unfortunately, programming the immobilizer requires special software, usually from an authorized dealer, depending on the vehicle make and model.
There are locksmiths who can access the programming software/information and can reprogram the immobilizer for you, which might be a little less expensive.
Vehicle Security
Car security is about two things, then: Entry to the car and starting the car. Most of the modern cars do not require you to insert keys to open the cars because they can be remotely locked/unlocked.
Minutes on their use, it does not take long to see many of the older remote car entry systems were still using RF systems, which means that they were nowhere near secure, since the RF signal could easily be intercepted and replayed to unlock/unlock and enter the car.
The modern entry locks use better RF-based systems and RFID systems that, on every entry, generate a completely new code. The vehicle is designed to create the same code so that two separate electronic devices remain synchronized all the time.
Some European manufacturers also used infrared systems that just required you to point the remote toward the car; however, now all vehicle manufacturers are using RF-based remote systems.
Transponder Operation
The early conventional vehicles did not have any kind of anti-theft system since there was a simple key lock system, and there may be thousands of similar key combinations that could have unlocked a car, and this too easy for thieves to take a vehicle easily.
Most of the new vehicles are constructed with certain types of ECU technology that allows them to use transponders for more security.
Transponder technology is now evident in many areas that require access security and is now synonymous with modern automobiles. Vehicle keys are now fitted with a transponder chip, and as the key is placed in the ignition, the transponder chip is engaged and activated by the radio frequency signal produced from the ignition barrel.
The chip transmits a signal to the car ECU, and when the signal corresponds, it disables the immobilizer to allow the engine to start.
Manufacturers are working to the point where you won’t need a key at all with fingerprint recognition.
Can I program my own key fob?
You can usually self-program the key fob for the locking and unlocking of the car, if that’s all you want to program. Although it’s nearly impossible to program a key for the start function without the proper tools for most modern car models.
How much does it cost to program my key fob?
To program the key fob for the lock and unlock function, you can usually do it yourself at no cost for most car models. For the immobilizer functions, you should expect a total cost of 200$ to 500$ for reprogramming on-site at a workshop.
How to program a key fob with push start?
For the most part, to program a key fob with push start, you will need the proper diagnostic tools because of the immobilizer, since the tools are usually just for dealers. However, to reprogram the unlock and lock functions, the procedure is the same as a standard key fob.
How to erase key fob memory?
To erase the key fob, you will need a suitable OBD2 diagnostic tool. Not all general scanner tools can erase key fob memory. You usually need a key fob eraser for your car model.
Can I program a key fob without going to the dealership?
Yes, you can program the unlocking and locking function of a key fob without having to go to the dealership. However, if you need to program the transponder to allow the key to start the car, you may have to see the dealership or a locksmith.
Does the key fob need to be reprogrammed after replacing the battery?
In most cases, key fobs will not lose memory simply because you have changed the one battery. If the key fob does not work after you change the battery, you probably put the battery in backwards. There are some vehicle models for which the key fobs may lose memory if you remove the battery, but that is rare.
In most vehicle models, to program a key fob, you have to insert the key into the ignition, press and hold the lock or unlock button on the key, and cycle the ignition two or three times while you are holding the button.
You will hear a lock sound, and then you will be allowed to remove the key, and you can then exit the car and try to lock or unlock
Programming car keys can be a bit of a complex topic, but if you do a little research and have a basic understanding, it is easy to develop a good understanding of the basic function of the system.
It is usually a relatively simple process to program a key fob for a central lock system, but if you want to program for an immobilizer, you may have to contact a professional.
I hope this guide helped you program your key fobs and taught you a little about what to do when you have an issue with your key fob.