Why can't the car key unlock the car even though it has power?

[DeRowan]

The reasons why the car key has power but cannot unlock the car are: 1. The control unit of the key is broken, and the central control unit cannot receive signals from the key; 2. The matching code of the key has expired, and it needs to be re-matched using a computer; 3. A fault in the central locking system, possibly due to a blown fuse in the door lock circuit, leading to an open circuit; 4. The presence of a signal blocker (such as a transformer) in the location of the owner and the vehicle, which interferes with the signal between the key and the central control unit; 5. A virtual soldering issue in the power distribution box, where poor contact due to virtual soldering can also cause the sensor to malfunction, requiring repair at a professional auto repair shop. All remote keys have a mechanical key hidden inside the remote key; simply take out the mechanical key to open the car door with the physical key.