Diagnostic article Generic OBD-II
P0BFA: motor B phase W offset must be read despite a copied phase label
GM P0BFA evaluates phase W offset with the power stage open, while a source sentence uses a conflicting phase name.
Read before applying this article
Documented application
GM 2010 10OBDG10 Hybrid Diagnostics, cited BPCM or hybrid-controller monitor only. Historical calibration values are not universal specifications; no per-code model, engine or hardware fitment has been established.
The code alone does not identify a failed part or establish that a vehicle is safe to drive. Confirm the vehicle, reporting module and applicable service procedure.
P0BFA is the motor B phase W current-sensor range/performance code. The GM row identifies phase W in its heading and malfunction quantity, describing an offset-current check rather than a direct low or high electrical-range test.
Follow the offset-specific evidence
The threshold is phase W offset above 30 A. The controller must be awake, the power stage OPEN, and the phase W range faults P0BFB/P0BFC inactive. The timing field lists 100 counts at a 2.08 ms rate, with 208 ms shown for the evaluation.
A useful diagnostic capture includes the offset quantity and power-stage state. Running phase current and an offset reading under the prescribed state are different observations; treating them as interchangeable can lead to the wrong diagnostic path.
Confirm the channel against service information
The strategy-description sentence calls the offset U-phase despite the W-phase heading and measured quantity. This inconsistency is retained for review rather than silently rewritten. It does not justify guessing a sensor location or a pin assignment.
The table provides no manual calibration adjustment or mandatory replacement. OPEN is an internal controller state, not proof of safe workshop isolation. Physical inverter work requires the exact vehicle's high-voltage procedure and trained personnel. Verification should establish credible phase W sensing and an eligible performance result after the actual cause has been addressed.
Source and applicability
GM 2010 10OBDG10 Hybrid Diagnostics, cited BPCM or hybrid-controller monitor only. Historical calibration values are not universal specifications; no per-code model, engine or hardware fitment has been established. GM PDF, physical page 297.
Article source documents
Source checks describe how the text was prepared; they do not certify a diagnosis or confirm compatibility with every vehicle using this code.
Original code reference
Dictionary definition
Drive Motor B Phase W Current Sensor Circuit Range/Performance
This definition retains its original catalog scope. The article above is limited to its explicitly documented application.
Reference scope
Generic OBD-II definition.
A manufacturer label does not establish the model, year, engine or module to which a diagnosis applies. Read the safety and diagnostic limits.
Definition source
- DTC Database: pinned community code definitions
Source checked · MIT