When the battery of the car remote runs out, it will stop responding and the result is your car theft alarm goes off without you being able to stop it. The battery inside your car remote normally will last for around 3 years. In order to change the battery, you just need to go to your nearest watch repair shop and buy the battery, which in my area costs around Rs.30 per piece. In most cases, there will be two batteries inside the car remote key. Replace both and your remote should be working fine.