U012FLost Communication With Generator B Control Module
- Generic OBD-II code · Network
- How the car detects it
- U012F is reserved for vehicles with a second generator, labelled B, whose regulator or control electronics talk to the powertrain or hybrid controller over a bus. That can be a second alternator on heavy-duty trucks or a further motor-generator in a hybrid drive. No manufacturer explains U012F in an open document; the closest documented case is the A unit under U012D, where Ford's smart alternator hangs on a LIN line and loses contact through wet connectors or chafed wires. CARB's network monitoring rules apply in the same way. If generator B goes quiet, the controller can no longer set its output, so charging power drops and the battery or high-voltage system may run short. U0120 covers a starter generator.
- What you may notice
- Charging system warning
- Battery voltage falls during driving
- Hybrid system warning or reduced electric drive on hybrids
- Likely causes
- LikelyWet or corroded connector in the bus line to generator B
- PossibleFuse, power or ground of the generator B electronics missing
- PossibleBus wire chafed against engine or bracket
- RareGenerator B regulator or control module faulty
- Repair
- Medium · Usually a job for a workshop.Typical cost: €60 – €1,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.