What to Do When the Car Key Doesn't Work After Just Replacing the Battery?
2 Answers
Smart keys can emit infrared signals, which can unlock one or two doors, the trunk, and the fuel filler cap, as well as operate the car's windows and sunroof. If the car key stops working after replacing the battery, the following situations may occur: 1. Coding failure. The solution is to insert the key into the ignition and turn it repeatedly, being careful not to start the car. After repeating this four or five times, press and hold any button on the key to recode and reactivate it. 2. There may be a leakage fault in the circuit board inside the remote control, or a button may not have popped back up. The engine will only start when the central processor detects that the key is inside the car.
I just replaced the key battery but it still didn't work, and I was confused at the time. Later, I realized that the battery might not have been installed properly—it needs to be firmly secured, as even slight looseness can cause poor contact. I also used a flashlight to inspect the metal contacts in the key slot and noticed a green oxidation layer. I vigorously rubbed the copper contacts with an eraser to restore them. If you've installed an electronic radar detector or dashcam in your car, it could easily interfere with the signal, so it's best to move them away and test. If that still doesn't work, the issue might be with the internal circuit board, and you might need to consider replacing the key. However, don't rush to buy a new one—first, test if the spare key can start the vehicle, which is more reliable. I had to tinker with it twice before getting it right; this thing is all about meticulous operation.
