What is the reason why the car key doesn't work well after replacing the battery?
2 Answers
The reason why the car key doesn't work well after replacing the battery is: the key code fails, and the solution is: 1. When the car door is unlocked, press the unlock button on the car key; 2. Insert the car key into the ignition switch and start the car; 3. Turn off the engine and pull out the car key; 4. Press the lock button on the car key to complete the decoding. The functions of the car key are: 1. After turning off the engine and getting out of the car, long press the lock button on the key to remotely close the windows; 2. Long press the unlock button of the trunk and it will automatically pop open; 3. After pressing the car finder button, the car's horn will sound and the hazard lights will flash, making it easy to quickly find the car in a crowded place; 4. Press the open door button to only open the driver's door, and press it twice to unlock other doors.
Last time I replaced the battery in my car key, it didn't work afterward. Upon closer inspection, I found that installing the battery backward was the main issue—reversing the positive and negative terminals directly prevented the current from flowing. Another possibility is poor contact with the new battery itself, requiring it to be pressed firmly or repositioned, as oxidation or dirt on the internal contacts of the key can also hinder conductivity. Additionally, not checking whether the battery model matched the old key and casually buying one with a different voltage would naturally prevent it from working. I recommend reopening and reinstalling it to ensure a snug fit, while also using an eraser to clean the copper contacts and remove any oxidation. If it still doesn’t work, there might be an internal short circuit in the key or the buttons might be stuck due to wear—try gently cleaning the gaps around the buttons. Finally, some smart keys require reprogramming, such as pressing specific key combinations to reactivate, so don’t forget to check the manual. If all else fails, quickly take it to a repair shop to avoid getting locked out of the garage.
