If your seat leon key fob has stopped working it's not necessary to be replaced or changed in programming. You should first check the battery. Most fobs come with an adjustment switch, slider or small gap you can use to pry open and replace the battery. Make sure to use the same kind of battery as the original.
Dead coin battery
One of the most common causes of the key fob not functioning is the battery is dead. It is easy to replace, and takes only about a minute. However, you should first make sure that you are using the correct kind of battery. The majority of key fobs utilize CR2032 3V batteries, which can be found at most electronics stores and online. Your owner's manual, or a YouTube video will provide the instructions on opening the key fob, and then replacing its battery.
Water Damage
Even if your Leon key fob is waterproof, a prolonged exposure to salt water may damage the internal electronic chip that controls the remote. In some instances this can also block the key fob from connecting to the vehicle. To fix this, you will need to clean the chip with isopropyl alcohol or an electronic cleaner and dry it completely before replacing the battery.
If the battery isn't the problem, it could be that the buttons are misaligned or stuck due to a lot of use. A careful visual inspection will show if they are loose or damaged, and can be carefully put back together. You could do it yourself, or you can take the key fob to an auto repair shop to be repaired. Depending on the severity of the problem you may need to replace the entire remote.
Contacts of the battery may be damaged.
One of the most frequent reasons for a key fob to stop functioning is due to defective battery contacts. This could be due dirt or water in your key fob's case, or simply wear and tear. The solution is to clean the battery contacts using isopropyl alcohol. This will restore communication between the microprocessor, the battery, and the key fob.
You can change the battery in your Leon key fob by prying open the two halves using the help of a small screwdriver, and then removing the old battery. You can purchase a new battery from any electronics retailer. Follow the steps in the owner's handbook when removing the old battery and installing the new one.
You can also try resetting the remote keyless system by disconnecting the battery's 12 volts for a few minutes. This will reset your on-board computer components and allow your key fob to communicate with your car. If the problem persists you should consult a dealer to reprogram the key. They will employ an OBDII scanner to diagnose the issue and could be capable of reprograming your key fob without the need to purchase an original key. The process usually takes within less than an hour. The dealer can also reset the immobilizer.
Water damage
It's important to take action quickly if your key fob has been submerged in water. Water and electronics don't work well and can damage the circuit board. A key fob that is wet will also stop working. This is why it is essential to repair the issue as soon as you can.
If you accidentally dropped your keyfob into water or a pool, or washed it accidentally then you must remove the battery first and let it dry completely. You can also use paper towel or tissue to dry the outer casing. You can also place it in a bag that is filled with silica gel packs to help absorb moisture.
Once your key fob is dried completely, it's now time to put it back together. Make sure the battery is properly inserted and the metal contacts on the circuit board are clean. You could use a small amount of alcohol to clean these areas if needed.
You should be able to begin your vehicle using the fob of your key after all this. If it still won't work it could be necessary to resolve other issues. It could be a damaged key or a transponder which needs to be reset.
A malfunctioning receiver module
It may be time to replace your receiver module if you have tried everything, including replacing the batteries, reprogramming or using an extra key fob. The electronic component transmits signals to the other modules inside the car, including the immobilizer. Without a functioning receiver module, the car's security system won't work and you won't have the ability to start your vehicle.
If the receiver module in your seat leon is damaged or not transmitting appropriate radio frequency signals, you'll see an error message on the instrument panel. In most cases, the issue can be resolved by connecting an OBDII scanner to the diagnostic port of your vehicle and checking for errors. You can then try making a new program using the key programmer supplied by your dealer to determine whether it solves the issue.
Key fobs endure quite a beating but they're not impervious to destruction. The battery terminal contacts and button are among the most frequent failure points. With a little effort, you can repair or replace these. If the key fob batteries in your car aren't functioning properly test the voltage using a voltmeter. If the battery is showing less than 3 Volts it is time to replace it. You can get an replacement battery at any auto part or electronics center.
