What are the reasons why the car key has power but cannot be sensed?

[DiDakota]

There are several reasons why a car key has power but cannot be sensed: 1. Key fob malfunction: This could be due to damage from mechanical impact on internal circuits or burnt transmitter components caused by water exposure. 2. Dead battery: The car's sensor cannot function and thus cannot receive signals from the key. 3. Electromagnetic interference: If the environment has strong electromagnetic interference, it can disrupt signal transmission. 4. Poor soldering in the power distribution box: Loose connections from poor soldering can cause sensor failure. 5. Faulty sensor module: This is equivalent to losing the "receiver," making signals from the car key ineffective.

[LeonardoLee]

It's quite common to encounter situations where the car key has power but isn't being detected while driving, mainly due to several reasons. First, the chip in the key itself might be faulty—even with a new battery, aging or poor contact in the chip can prevent the signal from transmitting. Second, there could be significant environmental interference, such as being near large billboards or elevators in parking lots, as those metal structures can block wireless signals. Additionally, the car's receiver might be malfunctioning; located near the door, it can fail due to water damage or prolonged use. Sometimes, it's an operational issue, like the key not being placed within the correct detection range—it's best to try moving it closer to the start button. I recommend taking care to protect the key, avoiding keeping it in a pants pocket where it might get damaged, and periodically checking the entire system at a repair shop.

[Mildred]

As someone who frequently works on car repairs, I believe the key issue when a car key has power but fails to function lies in the signal transmission process. It could be that the key's RF module is damaged—power is present but no signal is transmitted; or the car's receiving antenna is damp and short-circuited; a circuit fault, such as a blown fuse; or the pairing program is lost and needs to be reprogrammed. Environmental factors play a significant role—signal strength is weak in basements or when there's interference from other car keys, causing the induction to fail. It's recommended to open the key and check if the chip is oxidized, clean the contact points, and if that doesn't work, use professional equipment to test the signal strength—most problems can be resolved this way.

[EliasDella]

I've encountered this weird issue before where the key fob clearly has battery but just won't unlock the door. Common causes include electromagnetic interference (like parking near high-voltage power lines), damaged key fob casing blocking the signal, the car system needing a reboot, or being too far away since the sensing area is usually within 1 meter near the driver's side. Avoid storing keys with smartphones to minimize interference. When searching for your car, try standing closer to the driver's side door.