P2B01: Cylinder 2 injector movement is not confirmed for a commanded pulse

P2B01 is the cylinder 2 injection-pulse performance diagnosis in the reviewed GM source. It looks for the electrical signature associated with injector pintle or armature movement, rather than judging cylinder 2 solely from a misfire or average fuel-trim reading.

The feedback is movement-related evidence

The ECM samples voltage across injector enable and command wires. Movement changes coil flux, allowing the controller to calculate an opening-magnitude value. A missing detectable opening or a value failing the calibrated missing-pulse comparison produces the diagnostic evidence.

A commanded pulse can thus exist without the expected detected opening. However, this is still an inferred movement test, not a direct fuel-flow measurement or proof that contamination caused mechanical sticking.

Evaluate the correct events

The small-pulse diagnostic must be enabled and voltage-feedback data must be ready. The source lists 50–100 samples evaluated at cylinder events. A recording taken outside eligible pulse conditions can miss the evidence even if the engine is running normally at that moment.

Use the applicable engine's cylinder numbering and retain the raw diagnostic status where available. The separate P2B09 monitor adds catalyst-warm-up eligibility for cylinder 2; its absence does not automatically negate a general P2B01 event.

Verification should establish expected opening feedback for the commanded cylinder 2 pulses and a completed monitor without recurrence. The table documents Type B, two-trip behavior, but does not identify a particular connector, pulse voltage for manual probing or required injector replacement.

Source and applicability

This description is limited to the stated monitor; vehicle, engine and calibration matching remain necessary. GM diagnostic table, PDF page 669.