Key fobs are incredibly convenient, allowing us to remotely lock, unlock, and even start our cars. However, this convenience relies on a small battery, and when that battery dies, you can be left stranded or facing frustrating malfunctions. Many car owners opt for generic replacement batteries for their key fobs, assuming they are all created equal. But as one BMW owner discovered, this isn’t always the case.
Recently, a BMW driver experienced a puzzling issue after attempting to replace their key fob battery. They opened a fresh, unopened Sony CR2032 battery, a common type for key fobs, and installed it. Despite the new battery reading a healthy 3.1 volts, the key fob remained unresponsive. Thinking it might be a faulty battery, they tried a second, also brand-new Sony CR2032. Still no luck.
Frustrated, the driver visited their BMW dealership in San Francisco. The service advisor presented them with a few options, none of them cheap. They could try a BMW-branded CR2032 battery for $9, which seemed reasonable. If that didn’t work, a remote diagnostic would cost $458. And if the remote itself was the problem, a replacement would be a hefty $650, on top of the diagnostic fee. Alternatively, they could skip the diagnostic and just replace the remote for $650. Facing a potential bill of up to $1100 versus a $660 replacement cost, the owner considered a Bimmertech key fob as a potentially more affordable aftermarket option at $485.
Before committing to expensive repairs, they decided to try the $9 BMW battery. To their surprise, it worked immediately! Intrigued, they spoke with the parts department, asking if this was a common issue – customers replacing their key fob battery with a fresh, generic one, only to have it fail. The parts specialist confirmed it was indeed a frequent occurrence, happening at least once a month. This suggested that there might be more to key fob batteries than just voltage.
The owner then re-checked the first Sony battery that had read 3.1v earlier; it now read only 2.7v. This inconsistency, combined with the fact that another Sony battery reading 3.0v did work, added to the mystery. While the exact reason remains unclear, the experience highlights a crucial point: not all CR2032 batteries are equal when it comes to key fobs. It’s possible that some vehicles, like BMWs in this case, might be more sensitive to battery specifications or require a certain level of consistent power delivery that generic batteries may not always provide.
For anyone experiencing key fob issues after a battery replacement, this story offers a valuable lesson. Before assuming a more serious and costly problem, try a brand-name battery, or even a battery specifically recommended by your car manufacturer. It could save you significant time and money. While generic batteries often work perfectly well in key fobs, this case serves as a reminder that sometimes, especially with sophisticated car electronics, the small details can make a big difference.
