Experiencing issues with your 2016 Toyota Corolla key fob? It can be frustrating when your key fob suddenly stops working. Like many, you might assume a simple voltage test is enough to determine if your key fob battery is still good. However, as one owner discovered, that’s not always the case, especially with the CR2016 coin cell batteries commonly used in these devices.
Initially, after a replacement key fob from eBay started malfunctioning, the immediate thought was a faulty battery. A voltmeter reading of 2.5v from the no-name battery that came with the fob seemed to confirm this suspicion. Even “fresh” Panasonic batteries, purchased a few years prior but with a seemingly valid expiration date of 12/2022 and testing at 3.3v, failed to resolve the problem. This led to confusion and the question: what’s really going on with these 2016 Corolla key fob batteries?
The turning point came with a trip to the store for a brand new Energizer CR2016 battery. Upon installation, the key fob sprang back to life. Surprisingly, this single new battery fixed not just the problematic fob, but all four key fobs, which were tested and found to be working again. This experience highlights a crucial lesson regarding 2016 Corolla key fob batteries, and likely batteries in many car key fobs: voltage readings alone can be deceptive.
Just like a car battery, a small coin cell battery like the CR2016 can show a good voltage reading but still fail under load. This is because over time, or due to manufacturing variations, the internal resistance of the battery can increase. A voltmeter only measures the open-circuit voltage, which doesn’t reflect the battery’s ability to deliver current when needed by the key fob. Those “fresh” batteries, despite their voltage and expiration dates, had likely degraded over time, stored in a garage drawer.
The solution is straightforward: when your 2016 Corolla key fob acts up, especially if it’s been a while since the battery was changed, don’t rely solely on a voltage test. Instead, try a brand new CR2016 battery from a reputable brand like Energizer or Duracell. It’s a cheap and simple fix that can save you a lot of headache.
To further ensure your batteries are reliable, consider load testing them, especially if you have older batteries on hand. There are specialized load testers for coin cell batteries, or you can even create a simple DIY tester, like the one described in this helpful guide: Simple Battery Tester for Coin Cells. This method provides a more accurate assessment of a battery’s health than voltage alone.
Finally, a practical takeaway for 2016 Corolla owners and anyone using CR2016 batteries in their key fobs: avoid buying batteries in bulk unless you plan to use them immediately. Coin cell batteries, like all batteries, have a shelf life, and storing them for extended periods, even under seemingly ideal conditions, can lead to performance degradation. It’s best to purchase them on demand when you need a replacement to ensure optimal performance and longevity for your 2016 Corolla key fob.
