Citroen C3 Key Fob Troubleshooting
Citroen c3 key fob can stop working for many reasons. These include worn buttons poor contact between the battery and the water, and receiver module issues. Make sure the batteries are 12 volts.
Deprogramming could be the cause that your key fob isn't unlocking your car. This occurs when certain buttons send an indication to the onboard computer to erase the key from its access list.
Dead coin battery
If your Citroen C3's key fob has stopped working The first thing you need to check is if the battery is dead. The batteries inside the fobs are small, round coins that can be easily replaced in just a few minutes. They are available at the general stores, home improvement stores, and a few auto parts stores. Be sure to purchase the correct type, though. Batteries for fobs are usually CR2025 or CR2032, however you should check the owner's manual for your vehicle to determine what type is required.
Before replacing the battery, take off the button pad and rub it with cotton swabs and alcohol. These will help remove corrosion, and clean the contacts that are usually gold-colored. Once the contacts have been cleaned, you can insert the new battery. Be careful not to mix the two types as they differ in voltage, dimensions and shapes.
The next step is to test the battery's voltage. You can get an accurate reading using a multimeter which is set to the battery's voltage range. If the battery's value is in the middle or above the threshold, then it needs to be replaced. You can also try the car's start using an additional key, however it may not be effective in all cases. If the issue persists, visit an CITROEN dealership with your V5 registration number and personal identification documents. A CITROEN Dealer can retrieve the code for your vehicle's immobiliser and order the replacement battery.
Water damage
If the key fob is submerged it may lose its signal. It is recommended to remove it as fast as possible from the puddle or pool. Once you've done that then use a cotton swab, isopropyl or electronic cleaner to dry the circuit board. If it still doesn't work, it may be the right time to purchase a new key fob.
Signal interference is a common reason for Citroen remote controls not working. This could happen when there is a strong electrical field close to the vehicle, or from other transmitters on the same frequency. When you leave the interference area, your key fob will restart working.
The Citroen C3 key fob might not function because of worn buttons signals, signal interference issues receiver module problems, a dead 12-volt battery, or a defective chip. If this happens, you'll need to get it reprogrammed by an expert. This can be done by a trained mechanic or at a Citroen dealership. If the issue is significant it is possible to replace the device. This is a relatively simple and affordable fix, but it's important to act quickly. The longer you take to address the issue, the more serious it will get. If citroen berlingo van key replacement doesn't get resolved the issue could be a hazard for passengers and you.
Receiver Module Issue
If your key fob ceases working, it might be because the receiver module has developed an issue. This can be caused by a number of things like water damage. It can happen when you drop your keys, or wash them. You can try to resolve the issue by removing and cleaning the chip using isopropyl ethanol or electronic cleaner. This will prevent the chip from corroding.
You can reset the receiver module if you disconnect it from the battery for 10 seconds. Then, reconnect the battery to the vehicle and repeat the process. If this fails to fix the issue, visit a dealership to get it replaced.
Interference can cause your key to stop working. This could be caused by other transmitters on the same frequency, or by objects inside your vehicle. If you're not able to fix the problem, you can go to a dealership to have your key fob reset.

The key fob contains a short-range radio transmitter/radio-frequency identification (RFID) chip and antenna, which sends a distinct coded signal to the receiver module in your car. If the signal is not right it will not recognize the car key and display a message saying "key not detected". This can be a frustrating issue especially when you attempt to start your car.
Dead 12 volt battery
If your key fob stops working after a battery change It could be damaged. This is more frequent when the key fob been dropped or stepped over However, it can happen after a service that requires the removal of the panels and reinstallation. Wires are exposed when these panels are removed. If your fob is damaged, you may require replacement completely.
Another possibility is that the remote may be receiving interference from other devices or locations. The RF signals can cause to weaken and block the car from recognizing the remote. If this is the case you can reset all on-board computers by disconnecting the battery with 12 volts for around 15 minutes. This will remove any remaining electrical charge and allow the system to restart again.
Before replacing the battery, it's important to make sure that it's the right size and type. The circuit board on the key fob can be damaged when the battery you replace is too big or has different voltage. Before installing a battery you should clean the chip inside the fob to remove any contaminants that could cause corrosion. Making sure you choose the right battery can help ensure that it is properly sealed and shielded from moisture. Once the key fob is reinstalled, it should work normally. You should be able to use the second key even when your car displays a message that says "key not detected." It might be necessary to press the button several times before it responds.