Hi.
I would like to ask for help with an unusual problem. I have recently replaced the CR2025 battery in my key (Seat Leon III 2016) with a new Energizer battery:
.
Battery marked "fit for purpose" until 2026 so looks like a fresh supply. The problem is that 3 weeks after replacement, when starting the car on the computer a message pops up to replace the battery....
I measured the voltages and yes, there is a Panasonic battery in the other remote (spare). The voltage measured with a meter on the battery is 3.01 volts.
The battery in the key fob (Energizer) is 3.05 volts, I checked after pressing the button for example - 3.02 - 3.03 - a marginal drop.
I checked the 2nd battery from the blister (when I bought it there were two for replacement). A new unused battery has a voltage of 3.23 V.
Now to the question:
What could be the cause of the battery being identified as used despite the correct voltage? Could the fact that the new battery was 3.24 volts have messed up the electronics in the key, or switched something and now anything below 3.2 volts is reported as too low a voltage? As I mentioned the spare key has a weaker voltage and it is not identified as a battery to be replaced. Please help to unravel this conundrum.
I would like to ask for help with an unusual problem. I have recently replaced the CR2025 battery in my key (Seat Leon III 2016) with a new Energizer battery:

Battery marked "fit for purpose" until 2026 so looks like a fresh supply. The problem is that 3 weeks after replacement, when starting the car on the computer a message pops up to replace the battery....
I measured the voltages and yes, there is a Panasonic battery in the other remote (spare). The voltage measured with a meter on the battery is 3.01 volts.
The battery in the key fob (Energizer) is 3.05 volts, I checked after pressing the button for example - 3.02 - 3.03 - a marginal drop.
I checked the 2nd battery from the blister (when I bought it there were two for replacement). A new unused battery has a voltage of 3.23 V.
Now to the question:
What could be the cause of the battery being identified as used despite the correct voltage? Could the fact that the new battery was 3.24 volts have messed up the electronics in the key, or switched something and now anything below 3.2 volts is reported as too low a voltage? As I mentioned the spare key has a weaker voltage and it is not identified as a battery to be replaced. Please help to unravel this conundrum.

