P227EBarometric Pressure Sensor C Circuit Intermittent/Erratic
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- P227E covers a sensor C signal that jumps although every single value is in range. GM measures this as a string length: the absolute difference between each reading and the one taken 12.5 ms earlier is summed over 80 consecutive readings, and a sum above 152 kPa (2018 diesel) or 150 kPa (supercharged LT4) counts as a failure. Four failures in five one-second samples set the code, as Type B with two trips on the diesel and as Type A on the LT4. Loose terminals, chafed insulation, a cracked sensor housing or interference from nearby actuators are typical triggers. P227C and P227D catch steady shorts, P227B values that are smooth but wrong. The engine normally keeps running on a substitute pressure.
- What you may notice
- MIL on, possibly coming and going
- Occasional brief hesitation or uneven boost
- Likely causes
- LikelyLoose or corroded terminals in the sensor C connector
- PossibleChafed wiring with intermittent contact
- RareInterference from ignition or actuator wiring routed nearby
- RareSensor C with an unstable internal element
- 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: €30 – €400
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.