P227BBarometric Pressure Sensor C Circuit Range/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
- P227B means sensor C supplies an electrically sound signal that does not agree with the other pressure readings. In GM's 2018 diesel tables sensor C is the turbocharger inlet pressure sensor: the ECM compares it with BARO and MAP at idle and in the window between key-off and the next start, and if only sensor C is out of line it gets the blame, as a Type B fault after 320 failures in 400 samples. With the engine stopped a reading below 50 or above 115 kPa also fails. On GM's 2023-2024 twin-throttle engine the pressure ahead of a throttle is checked against ambient pressure while running and while stopped, with 2 kPa tolerance plus allowances for modelled air-filter loss; the code sets after 2 s within one trip. P227C to P227E cover electrical faults of the same sensor.
- What you may notice
- MIL on
- Mostly no driveability change; occasionally reduced boost
- Likely causes
- LikelySensor C drifting or with an offset
- PossibleSensor port blocked by dirt, oil or ice, or sensor not seated in its bore
- RareHeavily clogged air filter shifting the pressure ahead of the compressor or throttle
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Often possible to do yourself.Typical cost: €40 – €400
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.