Remote start keys function by sending a signal from the key fob to the vehicle’s engine control unit (ECU). When the correct signal is received, the car starts automatically, allowing it to idle until the driver is ready to enter. Some remote start systems also include keyless entry and trunk release, making them even more convenient for daily use. However, if the key fob’s battery dies or the signal becomes unresponsive, you may need a car key replacement to restore full functionality. A professional locksmith or dealership can program a new remote start key to sync with your car’s security system. Keeping an extra battery for your key fob can help prevent unexpected failures, ensuring your car remains accessible at all times.