My car has been giving me "key battery low" message for a little while, so it's time to get a new battery. I still have a required CR2025 battery on hand (probably there for a couple years already), so went ahead to try it. The key didn't operate at all with it. I tested the battery voltage: the current one has about 2.92V, and the replacement has 3.2V. This thread mentioned that old battery may not be able to deliver required current. I tested the replacement battery (using 200 mA ammeter) and it started with about 150mA reading and quickly dropped to stabilize at 60 mA. I also tried a CR 2032 I have (probably old as well) and that didn't work either. That one reads about 60 mA too. Maybe it's time to get some new CR2025 and see.
Update: the new CR2025s did work. I measured the battery being replaced, and its current read about 90 mA. The new battery has 3.3 V output (didn't measure the current).
