Seat Leon remote keys that suddenly stop working may be caused by a variety of factors. Some of them include: a dead battery water damage to the receiver module, radio interference, and damaged coin batteries.
Be sure to replace a lost or damaged key with the correct size and type. Also, make sure that the new key is programmed to your vehicle.
Dead coin battery
A dead battery for your coin is the most common cause of your seat leon's key fob not working. This is a straightforward fix that takes only a couple of minutes. However, the issue could be caused by damaged buttons, water damage or signal interference, as well as receiver module problems. These issues can be fixed with an OBDII scanner or reprogramming of the key fob.
The coin battery in the key fob is a vital component of the remote keyless ignition system in your Seat Leon. It has metal retaining clips to keep it in place and complete the circuit by sending power to the receiver module. If the clips become loose or are corroded, it could cause the circuit to fail. Replace the battery with a new one with the same type, voltage, and size to correct the issue.
If the key fob has been exposed to water it is recommended that you clean it with isopropyl ethanol and a paper towel. This will help to prevent further corrosion or damage. It is also recommended to allow the electronics to dry completely before replacing the battery.
Contacts for the battery that are defective
The key fob of your Leon features metal retaining clips that hold the battery in place and complete the circuit. Contact issues can occur if the clips aren't properly tensioned. This can also happen if you replace the battery with the wrong voltage or size. This can be corrected by replacing the old battery with a new one. Make sure you use the same voltage and size as the original.
The fob may also fail due to damaged battery contacts or water damage, signal interference or an unresponsive 12 volt battery. In this case, disconnect the 12 voltage batteries for a couple of seconds. Reconnect the negative and positive cables following that.
If your Seat Leon keys aren't working it could be the time to speak with a specialist auto locksmith. UK Auto Locksmith can help you with a wide range of services for your car keys, including reprogramming the key chip. They have affordable rates and are well trained to handle car keys repair requirements.

A malfunctioning receiver module
The key fob of a seat leon is a small device that transmits signals to the vehicle. The immobilizer system of the car may not function if these signals are not received in a timely manner. This can be due to interference from objects, poor weather conditions, or transmitters operating on the same frequency band. The key fob may still function within a certain range.
Metal clips keep the battery in place within the key fob. Contact points may fail if they're worn out, corroded or corrosion-prone. You can replace the battery in your key fob quickly however, you must make sure that it's of the same size and voltage as the original.
If your key fob does not work to start the vehicle, you may have to replace the receiver module or battery. This issue can be addressed by a professional at very little cost. They can also reprogram your key fob, which will save you money from needing to pay a dealer to perform the task for you. Professionals can also assist with other issues like an issue with your TIPM (transmission-immobilizer control unit). They can also help you replace the ignition switch or sensor.
Radio interference
The key fob uses radio waves to communicate with the car, however these signals may be mangled if there is a large amount of interference in the vicinity. This could be caused by satellites or broadcast towers. This type of interference can affect the range of your remote's range. If your remote is working from a short distance, try placing it near your head or chin to see if this fixes the problem.
In the majority of cases the case of a Leon key fob that stops functioning can be repaired by resetting the receiver module. This can be done by removing the battery for a couple of minutes (first then, the negative cable, and then the positive cable). Afterwards, seat arona key cover should be functioning as normal. If not, you may need to visit an authorized dealer to reprogram the. Alternatively, you can also use an OBDII scanner to identify the root of the problem. It is possible that the electronic chip within the key fob has developed a fault which requires replacement. This is more likely to happen in the event that the keyfob was exposed to salt or water.