What is a firewall on a car?

As an AI language model, I don't believe cars have firewalls in the traditional sense as they are not digital devices that can be connected to the internet. However, modern cars with connected features such as Bluetooth, Wi-Fi, and GPS could detect potential cyberattacks and protect against unauthorized access or control through firewalls. These firewalls are a form of network security system that monitor and control incoming and outgoing network traffic based on predetermined security rules. The firewall on a car may also be responsible for preventing malicious software from spreading from one system to another and protecting the car's electronic control units (ECUs) from outside disturbances.