

The most commonly cited reason for key fob malfunction is a dead coin battery. Other causes are water damage or a malfunctioning module and interference signals.
Dead Coin Battery
If your key fob's battery has gone out of service, the first step is to replace it. Make use of a new button battery that has the same voltage, size and specifications as the old one.
If the key fob has been exposed to water, like a splash of rain or salt water on the beach, it will have to be cleaned before it can be used again. A paper towel soaked in isopropyl alcohol or electronic cleaner can help.
If the key fob isn't working despite not being exposed to water, it could be due to a glitch in the receiver module, or even in the internal electronic chip. In these cases it is possible to re-programme the key fob with an OBDII scanner could assist.
Water Damage
You could have water damage to your key fob if it was submerged in a puddle, pool or washing machine. It is usually possible to get it working by taking out the batteries and cleaning the circuit board with ruby alcohol. It's a good idea to allow the fob to dry completely before installing a new battery.
If your key fob has stopped working, even after replacing the battery and programming it again, you might have a problem with the receiver module. You can find information on reprograming the majority of fiat punto remote key replacement locked keys in fiat 500 on YouTube or in the owner's manual. You could also try resetting the car's onboard computer using the OBDII scan tool.
Faulty Receiver Module
The key fob is equipped with the chip that communicates the vehicle's system. If the chip is damaged, it will be unable to longer send and receive signals to the vehicle. The key fob being dropped can result in this, as can water exposure. If the key fob stops working after water exposure it is possible to repair the issue by cleaning or cleaning the chip using isopropyl alcohol or electronic cleaner.
If the key fob does not respond to cleaning, it's likely that the module is in a fault and needs to be replaced. A damaged receiver module may also cause the remote control key to not function. This is usually caused by electromagnetic interference.
Faulty Electronic Chip
The electronic chip that is in your key fob is a vital part in the anti-theft security system of your vehicle. It sends a signal to the immobiliser unit in your car to determine whether the key is legitimate. Your car will not start in the event that the chip has been damaged.
A faulty chip may also be caused by interference from other objects, weather conditions or transmitters near your vehicle. In this scenario, a new fob will be needed.
Contacts of the battery may be damaged.
The battery contacts in the fiat 500 key fob reset fob are delicate and can get damaged with hard usage. If they're broken or bent, the fob will not send any signals to the receiver modules inside the car.
Modern fobs are constructed with rubber seals that keep out water. Submerging them in water even if it's only an occasional drizzle or splash could harm the chip's electronic components.
The key fob has an embedded chip that communicates to the immobilizer system of the vehicle, allowing it to start it. This system uses crypto coding systems in modern vehicles or the red key system used in older ones. This chip will have to be replaced if it's faulty.
The 12 Volt Battery is faulty
A damaged battery could cause the key fob to work. If this happens, the car's computer system will not be able to recognize that the remote is within the vehicle.
Test the battery with the voltmeter before replacing it to determine its capacity. A fully charged battery will display 12.6 volts. If the reading drops significantly it is time to replace the battery.
To test the battery's capacity to determine its capacity, put an electric load on it for a couple of minutes. This will take away 1percent of the charges. After that, measure the voltage. The longer the battery is able to hold its voltage, the better its capacity. The ideal is to keep it close to 12 volts during several minutes.
The radio signal is not working properly. Radio Signal
This is the main reason for the key fob not sending signals to the car. This issue can be resolved by replacing the battery. It is essential to purchase a battery that has the same dimensions and voltage as the original.
Fobs are subject to a lot of abuse, and they aren't impervious to destruction. The battery buttons and contacts are brittle and are susceptible to being bent or damaged from rough usage.
Other transmitters or objects that use the same frequency can also disrupt a signal. A light control panel in your home, for example, may interfere with key fobs using the same frequency. This could interfere with the fiat 500 remote key replacement control of your car.
Incorrect OBDII Scan Tool
There are many reasons why a scanner could not work. Some are more complicated than others.
Professional scan tools allow mechanics to examine the car's systems and conduct a variety self-tests. These tools can help save time, but are costly and not accessible to most DIYers.
If your OBD2 scan tool isn't turning on, make sure you check the voltage at terminals 16 (scantool power) and 4 (chassis earth). If they're both in good shape the chances are that a fuse has failed. This is the main reason for a scan tool to fail. The easiest solution is to replace the fuse which has blown.