This code generally triggers a "Battery Charging Fault" or "Check Stop/Start" message on your dashboard. It means the car's computer (UPC/EMM) has lost a reliable signal or power link with the alternator or the battery's current sensor.
Intermittent breaks in the wiring harness, particularly near the UPC or alternator connectors. Corrosion: dtc b123a renault link
If all wiring and handle are fine: