Powertrain, generic (extended)

P2B09 Cold Start Cylinder 2 Injection Pulse Performance

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

P2B09 reports that while the catalyst is being warmed after a cold start the ECM missed the opening trace of injector 2 on too many commanded pulses. CARB defines the window: at least six hours engine-off, ambient at or above −6.7 °C and coolant no more than 15 °C warmer than ambient. GM already ran the test in 2019 on the 2.7 L L3B, setting it after 100 failures in 380 samples, Type B. For 2021 Malibu, Equinox and Terrain (LYX and LFV engines) GM bulletin 20-NA-230 lists P2B08–P2B0B with P2B95 as a software anomaly: vehicles built before 2 December 2020 get the current calibration, then codes are cleared and a cold start is repeated. If P2B09 comes back, normal diagnosis follows; the warm-engine code is P2B01.

Likely causes

Outdated ECM calibration (GM bulletin 20-NA-230)
Cylinder 2 injector not responding to the short cold-start pulses
Wiring or connector problem on injector 2

Symptoms

  • Check engine light after cold starts on two trips
  • Usually no driveability issue once the engine is warm

Repair estimate

DifficultyEasyWorkshop job
Parts and labour€0–900
Time0.3–4 h

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

Parts involved

fuel injector cylinder 2injector wiringengine control module

Related codes

P2B01P2B08P2B0AP2B95P0202P0302

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