P0BFB: motor B phase W low is a disabled-output sensing check

P0BFB is the low-range diagnosis for motor B phase W current sensing in the cited GM document. The code concerns the controller's sensor report, not a conclusive measurement of physical motor current under ordinary driving conditions.

Interpret the range threshold in its context

The reported phase W output must be below −700 A. The source requires the wakeup signal on and PWMOutputEnable FALSE. That disabled-output state distinguishes this check from protection monitors evaluating excessive current during inverter operation.

Ten qualifying counts among fifteen at a 2.08 ms rate are specified. The two-trip reporting classification should be kept separate from this sample filter. Save the operating state and original code status along with the signal value when the event is investigated.

Do not overlook inhibited offset testing

The phase W offset monitor is unavailable while P0BFB or P0BFC is active. A missing range/performance code does not, by itself, establish that the channel's offset is normal.

The source does not identify a failed connector, require a particular part or give a safe current-injection method. Exact vehicle circuit information is needed to distinguish inaccurate sensing from other conditions. A qualified hybrid technician must establish high-voltage isolation independently; PWM disable is not sufficient evidence for safe access. Confirm credible readings and eligible monitor operation after repair rather than relying only on cleared memory.

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.