P2B00: Cylinder 1 injection pulse lacks the expected opening signature

P2B00 evaluates whether a commanded cylinder 1 injection pulse produced the expected injector movement in the reviewed GM monitor. The controller infers that movement from voltage-flux feedback in the injector coil; it does not directly measure the fuel volume delivered.

A command is not the same as detected opening

When the pintle or armature moves, the coil's electrical response changes. The ECM measures feedback across the enable and command wires and converts it into an opening-magnitude metric. Failure can involve no detectable opening magnitude or an opening magnitude outside the calibrated missing-pulse criterion.

This distinction explains why seeing an injection command alone is insufficient to show that the monitored event succeeded. Equally, the feedback result does not prove the exact mechanical cause or establish spray quality.

Data readiness is essential

The small-pulse general diagnostic enable and fuel-pulse voltage-feedback-data-ready flags must both be true. The table specifies 50–100 samples with cylinder-event sampling. The elapsed time needed to gather evidence therefore depends on eligible cylinder events, not merely a fixed number of seconds after starting.

Confirm cylinder numbering for the actual engine and preserve pulse command, feedback validity and operating conditions. P2B00 is the cylinder-specific general monitor; the separately documented P2B08 adds catalyst-warm-up eligibility for cylinder 1.

Verification should show a valid opening signature through the applicable completed test. Injector electrical and fuel-system work should follow professional service procedures. The source lists Type B, two trips, but does not mandate 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 668.