P2B0BCold Start Cylinder 4 Injection Pulse Performance
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- P2B0B covers cylinder 4 during the cold-start strategy and in GM's tables belongs to four-cylinder and larger engines. GM's 2025 four-cylinder table sets the window via P2B95 differently from the three-cylinder: catalyst below 400 °C, 450–2,800 rpm, pedal up to 35 % and less than 100 s run time, so the test may continue while pulling away. The cylinder code itself is Type B after 50 to 100 samples. GM bulletin 20-NA-230 (2021 Malibu, Equinox, Terrain) treats P2B0B as a software issue solved by a new calibration; engineering information PIE0808 for the 2023–2024 Colorado and Canyon 2.7 L names it among codes still being investigated, with a harness check and fuel rail connector reseat. Warm-engine faults on this cylinder are P2B03.
- What you may notice
- Warning lamp after cold starts
- Possibly slightly uneven running during the first minute
- Likely causes
- LikelyECM calibration needing an update (GM bulletin 20-NA-230)
- PossibleHarness damage or poor contact at the fuel rail connector (GM 2.7 L)
- RareCylinder 4 injector sluggish at low temperature
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €0 – €900
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.