P227DBarometric Pressure Sensor C Circuit High
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- P227D is the high-voltage counterpart of P227C. On GM's 2018 diesel the sensor C input has a pull-up, so both a short to the supply and a broken signal wire push it above 90.2 % of 5 V (about 115.4 kPa); after 320 failures in 400 samples it is a Type B fault. The supercharged LT4 uses 90 % (115 kPa) and attributes the code only to a short to power, here as Type A with the MIL on the first trip, because its input reads an open line as low. GM's 2023-2024 twin-throttle engine flags a reading above 115 kPa held for 2 s over two trips. Since the atmosphere cannot produce such a value at the sensor positions concerned, the ECM switches to a substitute, and corrections for altitude or boost become less exact.
- What you may notice
- MIL on
- Little change in driving; possibly reduced boost or poorer altitude compensation
- Likely causes
- LikelySignal wire of sensor C shorted to 5 V or battery voltage
- PossibleBroken signal wire or sensor ground on inputs with pull-up
- 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.