P227A code meaning
Barometric Pressure Sensor C Circuit
Powertrain system Generic code P22xx codes Check engine light
What P227A means
P227A is the general circuit fault of barometric pressure sensor C, used when the control unit finds the signal missing or unusable without classifying it as too low or too high. Sensor C is not necessarily a separate ambient sensor: in GM's 2018 diesel tables the BARO C channel belongs to the turbocharger inlet pressure sensor, GM also uses it on the supercharged 6.2 L LT4, and on its 2023-2024 twin-throttle engine it reads pressure ahead of a throttle. No manufacturer documents P227A itself publicly; GM divides circuit monitoring of sensor C into P227C (low), P227D (high) and P227E (erratic). The matching general codes for sensors A and B are P2226 and P222A. With a substitute value the engine keeps running, but altitude and boost corrections lose accuracy.
P227A 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 repairWhen cleared with a scanner
Symptoms of P227A
- MIL on
- Usually no noticeable change in driving; slight power loss at altitude possible
Common causes of P227A
- Most likelyLoose connector, corroded pins or damaged wiring at sensor C
- PossibleSensor C itself failed
- Less likely5 V reference or sensor ground shared with other sensors disturbed
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Barometric pressure sensorSensor wiring
What each part of P227A 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). |
| 7A | The exact fault in that area. |
What to do next
- Note P227A 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 P227A
What does P227A mean?
P227A means "Barometric Pressure Sensor C Circuit". P227A is the general circuit fault of barometric pressure sensor C, used when the control unit finds the signal missing or unusable without classifying it as too low or too high. It is a generic code, so it means the same on every make.
Is it safe to drive with P227A?
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 P227A fail an emissions test?
Yes, it can. P227A 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 P227A 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 P227A clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.