BMW 3 Series Key Remote Not Responding?
2 Answers
It is recommended to replace the key battery first. If that doesn't work, check the battery voltage (normal voltage should be around 12.5V, and around 15V when charging). If it's below 12V, the battery may need replacement. Here's a basic introduction to the components of a remote key: 1. Transmitter: Consists of a transmission switch, transmission antenna (keypad), integrated circuit, etc. It contains an identification code storage circuit and an amplitude modulation circuit, with a button-type lithium battery on the opposite side of the circuit. The transmission frequency is selected according to the radio standards of the country of use, and the transmission switch sends a signal each time the button is pressed. 2. Receiver: After the transmitter sends the identification code using shortwave modulation, it is received by the car's shortwave antenna and enters the receiver's electronic control unit through a distributor for demodulation via a shortwave high-frequency amplification processor. The demodulated identification code is then compared; if it's the correct code, it is input into the control circuit to activate the actuator.
When the BMW car key remote doesn't respond, I think the most common issue is that the small battery is dead. That button battery tends to drain after prolonged use. You can open the key casing yourself and replace it with a new one, but be careful not to buy the wrong model—CR2032 is the most commonly used type. If it still doesn't work after replacement, there might be interference in the surrounding environment, such as parking near a radio station or strong signal devices. Try moving to an open area and testing again. Another possibility is that the key has been dropped or exposed to water, damaging the internal circuitry, which would prevent the signal from being sent. The electronic system in the BMW 3 Series is quite sophisticated, and sometimes even a faulty door receiver can cause this issue. So, I recommend manually locking the car first to confirm if it responds normally. If the door locks still work, the problem can likely be narrowed down to the key; otherwise, there might be an issue with the car's circuitry. For safety, don't delay too long to avoid being locked out if the key completely fails one day. It's best to keep a spare key for emergencies, and avoid storing the key in places like the fridge or high-temperature areas to extend battery life.
