Delving into the inner workings of modern car technology can be fascinating, especially when it involves something we use every day like a car key fob. Let’s take a closer look at the 2022 Bmw Key Fob Battery and the components within. This exploration comes from a hands-on teardown of a BMW key fob, revealing how surprisingly accessible these devices are.
Gaining access to the internal components of this key fob is quite straightforward. The design incorporates four plastic nubs encircling the CR2032 battery which need to be carefully detached. Once these are unclipped, a plastic pry tool is sufficient to gently separate the two halves of the key.
Here you can see the angled nippers used to clip those four plastic nubs, making the initial disassembly possible.
Upon separating the key fob halves, one side exposes a portion of the circuit board. Clearly visible are the lock and unlock button contacts, along with various microchips and what appears to be an oscillator crystal. It’s worth noting the presence of two additional plastic nubs which further secure the circuit board to this half of the key fob casing.
Further disassembly, involving the removal of these additional plastic nubs and gentle prying, allows for the circuit board to be detached from the key fob casing, fully revealing its other side. This side contains components that are speculated to be locking resistors, although their exact nomenclature requires further investigation. These components are believed to be integral to the vehicle’s onboard locking system communication.
Considering BMW’s history, particularly with their Electronic Immobilizer System (EWS) in mid-1990s vehicles, it’s plausible that similar principles are still in play within the 2022 BMW key fob. The following diagram from a BMW EWS document provides an interesting point of comparison:
The markings “L1” and “L2” on the PCB, as seen in the teardown, are indicative of inductors (“L” being the standard abbreviation for inductors). For those interested in a deeper dive into the EWS system, the complete PDF document is available at: http://www.unofficialbmw.com/images/BMW_EWS.pdf.
The EWS system traditionally relies on the vehicle itself to supply power to an inductive coil. This power is used to read and write to the EEPROM within the key each time the car is started.
In the context of a motorcycle, and by extension, modern car key fobs, the CR2032 battery likely serves as the power source for the EEPROM whenever the engine is initiated. This theory is reinforced by user manual instructions which, in some cases, direct users to insert their key into a slot on the vehicle – potentially to energize the key’s inductive coil and power the EEPROM, mirroring the EWS system diagram shown above where the vehicle’s ring antenna powers the key’s inductive coil. Older BMW keys lacked internal batteries and functioned solely within the ignition tumbler, eliminating the need for a dedicated key battery to power the EEPROM.
For those interested in reverse-engineering or simply examining the intricacies of the 2022 BMW key fob, here are a couple of high-resolution images:
Hopefully, this teardown provides a useful insight into the 2022 BMW key fob battery and its related technology.
