Powertrain, generic (extended)

P2B02 Cylinder 3 Injection Pulse Performance

Check engine lightOn

EmissionsRelevant

Drive cycleRequired

Limp modeNo

P2B02 concerns cylinder 3: in warm operation the ECM did not see the voltage bump that marks the cylinder 3 injector actually opening, often enough to count pulses as not delivered. On GM's 1.2 L LIH three-cylinder, cylinder 3 is the last one, and the 2025 table for that family (cylinders 1–3 only) decides after 50 to 100 samples, Type B. GM service update A202310450 for this engine in the Encore GX (2020–2021) and Trailblazer (2021) (about 22,350 US vehicles) lists P2B02 with P2B00, P2B01 and the cold-start codes; the cure is reprogramming the ECM, not new parts. On four-cylinder engines GM also monitors cylinder 3 with this code. Cold-start faults on the same cylinder are P2B0A.

Likely causes

ECM calibration with false detections (GM 1.2 L LIH, service update A202310450)

Cylinder 3 injector not lifting reliably

Damaged injector 3 wiring or connector

Symptoms

Check engine light, often without any driveability complaint
On a real injector fault rough running on cylinder 3 (P0303)

Repair estimate

DifficultyMediumWorkshop job

Parts and labour€0–800

Time0.3–4 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

fuel injector cylinder 3injector wiringengine control module

References: law.cornell.edu, gsi.ext.gm.com, static.nhtsa.gov.