Mini Cooper Key Battery Issue

Sounds like a frustrating issue. When you say keyless access isn't working, does that mean the auto key isn't recognized at all when you approach the car? Have you tried using the physical key to unlock the door as a temporary workaround?

Indeed, I have attempted utilizing the physical key as an interim measure. In response to your query, the electronic key is not recognized upon approach. Could the low voltage situation conceivably impede the functionality of the remote locking mechanism, even with a newly installed battery?

It definitely sounds like a dead key battery is the culprit. The low voltage could absolutely mess with the remote locking, even if you were to replace the battery yourself. I'd recommend getting it checked out at a workshop to confirm, just in case there's something else going on with the electronic key itself.

I wish to extend my gratitude for your assistance. As suspected, the fault was indeed attributed to the depleted state of the electronic key battery. Following a battery replacement, at a cost of 37€, the keyless access functionality has been restored, and the error has been cleared from the vehicle's error memory. All systems are now operating as intended.