4xe 12V Battery Parasitic Drain
SeriousElectrics & ElectronicsThe Telematics Box Module (TBM) can stay "awake," draining the 12V battery completely overnight. This is especially common if the vehicle is left plugged into a charger after reaching 100%.
Most affected: 4xe (PHEV) models
Typical symptoms
- •Dead battery after being parked
- •Stop/Start unavailable
- •"Service Hybrid System" warning
- •Vehicle unresponsive to key fob
What to inspect before you buy
- ✓Check battery health
- ✓Ensure TBM and BCM software updates have been applied