P227CBarometric Pressure Sensor C Circuit Low
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- P227C flags a voltage from pressure sensor C that is too low. GM's 2018 tables show two variants. On the diesel, where sensor C measures turbocharger inlet pressure and the input has a pull-up, only a short to ground pulls it below 39.4 % of 5 V (about 50.2 kPa); 320 failures in 400 samples make it a Type B fault. On the supercharged 6.2 L LT4 the limit is 40 % (50.9 kPa), and both a grounded and an open line count, as Type A with the MIL on the first trip. GM's 2023-2024 twin-throttle engine looks at the pressure value: below 50 kPa for 2 s, two trips. GM bulletin 22-NA-188 (1.3 L L3T and 2.0 L LSY turbo) links P227C after an ECM replacement to a redesigned MAF sensor that requires the matching calibration. P227D is the high counterpart.
- What you may notice
- MIL on, on some engines immediately
- Engine runs on a substitute value, at most slightly less power
- Likely causes
- LikelySignal wire of sensor C shorted to ground
- PossibleOpen signal or 5 V supply line on inputs that read an open circuit as low
- RareReplacement control module without the calibration that matches the fitted sensor
- RareSensor C internally defective
- 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.