P227B code meaning
Barometric Pressure Sensor C Circuit Range/Performance
Powertrain system Generic code P22xx codes Check engine light
What P227B means
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.
P227B at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium, DIY possible
- Typical labor0.5 to 2 hours
- Clears after repairAfter a drive cycle
Symptoms of P227B
- MIL on
- Mostly no driveability change; occasionally reduced boost
Common causes of P227B
- Most likelySensor C drifting or with an offset
- PossibleSensor port blocked by dirt, oil or ice, or sensor not seated in its bore
- Less likelyHeavily clogged air filter shifting the pressure ahead of the compressor or throttle
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Barometric pressure sensor
What each part of P227B means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 2 | Area: fuel and air metering (injector circuit). |
| 7B | The exact fault in that area. |
What to do next
- Note P227B and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P227B
What does P227B mean?
P227B means "Barometric Pressure Sensor C Circuit Range/Performance". P227B means sensor C supplies an electrically sound signal that does not agree with the other pressure readings. It is a generic code, so it means the same on every make.
Is it safe to drive with P227B?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P227B fail an emissions test?
Yes, it can. P227B is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P227B to fix?
Difficulty: medium. A typical repair takes 0.5 to 2 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P227B clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.