Experiencing issues with your BMW key fob? Often, the simplest solution is a battery replacement. Like many BMW owners, I recently encountered a frustrating situation where a seemingly straightforward battery swap turned into a bit of a saga. Let me share my experience and guide you through the process of replacing your BMW key fob battery, ensuring you avoid potential pitfalls and save money.
My BMW key fob started displaying an error message – something along the lines of a low battery warning. Thinking it was a quick fix, I grabbed a fresh, unopened Sony CR2032 battery (purchased in Jan 2019) from my stash. Voltage read 3.1 volts on my multimeter – seemingly perfect. But, to my surprise, the key fob remained unresponsive. I tried another new, unopened Sony CR2032, again with a good voltage reading. Still nothing.
Frustrated, I scheduled a service appointment at BMW San Francisco. The service advisor presented me with a couple of options, all involving potential costs:
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Option 1 (Trial & Error):
- Try a BMW branded CR2032 battery ($9.00).
- If that fails, a diagnostic test on the remote ($458).
- If the diagnostic fails, a key fob replacement ($650 plus the diagnostic cost).
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Option 2 (Direct Replacement):
- Try a BMW branded CR2032 battery ($9.00).
- Directly replace the remote ($650).
Facing a potential bill of $1100 versus a guaranteed $660 for a new remote, I briefly considered aftermarket options like Bimmertech key fobs at $485 ( https://www.bimmer-tech.net/category-bmw-key-fob ). However, before committing to expensive solutions, I decided to try the $9 BMW battery.
Talking to the parts department, I asked if this was a common issue – customers replacing batteries themselves only to find it doesn’t work. The parts guy confirmed it was surprisingly frequent, happening at least once a month. Intrigued and hopeful, I purchased the BMW CR2032 battery. And guess what? It worked! The key fob sprung back to life immediately.
It turns out, despite my initial battery reading 3.1v and a second reading later dropping to 2.7v, and even trying another Sony battery that read 3.0v but eventually worked – the key seems to be the brand. The original battery, even reading 2.9v, was still functioning albeit triggering a low battery warning. Two brand new Sony batteries failed to work initially, while a BMW branded one solved the problem instantly.
While I’m not an electrical engineer, this experience suggests BMW key fobs can be sensitive to battery brands, even if they are the correct CR2032 type and show a proper voltage reading. The good news is, for a mere $9 and a bit of time, I avoided costly diagnostics and a new remote.
Key Takeaways for Replacing Your BMW Key Fob Battery:
- Start with a BMW Battery: Before assuming a faulty key fob or expensive repairs, invest in a BMW branded CR2032 battery. It might save you significant time and money.
- Voltage Isn’t Everything: Even with a multimeter reading a good voltage on a new battery, it might not be compatible with your BMW key fob.
- Dealership Costs Can Escalate: Be aware of the potential for high diagnostic and replacement costs at BMW dealerships. Explore all options before committing to expensive services.
- DIY First: Battery replacement is a simple DIY task. Try this first before seeking professional help.
Ultimately, my $9 BMW battery purchase was a far cry from the potential $1100 bill. Hopefully, my experience helps you troubleshoot your BMW key fob issues and successfully replace your battery without unnecessary expense.
