P0B4FHybrid/EV Battery Voltage Sense E Circuit
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- Cell sense channel E is the fifth measuring path between the battery cells and the monitoring electronics; P0B4F means the controller sees it as electrically open. Ford's experience shows how serious this can be: on 2019-2020 Fusion plug-in hybrids P0B4F appears among up to fourteen open-line codes from P0B3B to P0B7C with a no-start condition, and the bulletin prescribes replacing the high-voltage battery. On the 2023 Mach-E and E-Transit the same family points to an intermittent flexible circuit at the BECM. GM's BECM logic needs 0.6 s of an open-line pattern, such as adjacent cells 1.3 V apart or a balanced cell under 36 mV, and stores the code as Type A.
- What you may notice
- No start
- Battery cannot be charged
- Stop Safely Now message while driving
- Likely causes
- LikelyBroken channel E sense lead, splice or bus bar contact
- PossibleInternal failure of the high-voltage battery (Ford Fusion PHEV)
- PossibleIntermittent BECM flexible printed circuit (Ford Mach-E, E-Transit)
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €100 – €9,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.