P227C code meaning
Barometric Pressure Sensor C Circuit Low
Powertrain system Generic code P22xx codes Check engine light
What P227C means
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.
P227C 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 P227C
- MIL on, on some engines immediately
- Engine runs on a substitute value, at most slightly less power
Common causes of P227C
- Most likelySignal wire of sensor C shorted to ground
- PossibleOpen signal or 5 V supply line on inputs that read an open circuit as low
- Less likelyReplacement control module without the calibration that matches the fitted sensor
- Less likelySensor C internally defective
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 P227C 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). |
| 7C | The exact fault in that area. |
What to do next
- Note P227C 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 P227C
What does P227C mean?
P227C means "Barometric Pressure Sensor C Circuit Low". P227C flags a voltage from pressure sensor C that is too low. It is a generic code, so it means the same on every make.
Is it safe to drive with P227C?
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 P227C fail an emissions test?
Yes, it can. P227C 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 P227C 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 P227C clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.