Powertrain, generic (extended)

P2B0A Cold Start Cylinder 3 Injection Pulse Performance

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

P2B0A stands for missed cold-start pulses on cylinder 3. For the GM 1.2 L LIH with its three cylinders it is the highest cold-start cylinder code, since that engine's 2025 table stops at P2B0A. The same table defines the cold-start window through the summary code P2B95: catalyst below 550 °C, coolant up to 66 °C, 250–3,000 rpm and less than 20 s after start, ending after 500 engine cycles at most – a very short test. Cylinder codes are Type B and decide after 50 to 100 samples. GM bulletin PIP5746 and service update A202310450 (2020–2021 Encore GX, 2021 Trailblazer) both list P2B0A; the cure is ECM reprogramming. Four-cylinder GM engines use the code for their cylinder 3 too. The warm-engine twin is P2B02.

Likely causes

ECM software anomaly on the GM 1.2 L LIH (service update A202310450)
Cylinder 3 injector reacting too slowly when cold
Injector 3 connector with poor contact

Symptoms

  • Lamp on, code stored only after a cold start
  • Engine runs normally once warm

Repair estimate

DifficultyEasyWorkshop 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

Related codes

P2B02P2B09P2B0BP2B95P0203P0303

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