How does a passtime device prevent starting. Does is shut off fuel or prevent cranking?

A passkey device prevents starting by interrupting the vehicle's ignition or fuel systems. This is typically achieved by disabling the engine control unit (ECU) or cutting off fuel supply, which prevents the engine from running. In some cases, it may also prevent the starter motor from cranking, ensuring that the vehicle cannot be started without the correct key or code. Overall, it enhances security by making unauthorized vehicle operation difficult.