P222CBarometric Pressure Sensor B Circuit Low
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- P222C flags a sensor B voltage that has dropped too low, as with a signal wire touching ground. GM's 2018 tables for the 3.0 L LGW set the code below 40 % of the 5 V range, equal to about 50.9 kPa, counted in 320 of 400 readings taken every 12.5 ms; it is a Type B fault with the MIL after two trips. GM's 2023-2024 tables for a twin-throttle engine use the pressure value itself: below 50 kPa for 2 s. In GM software the fault bundle for ambient pressure sensor 2 covers exactly P222C and P222D, which tells which sensor letter B refers to there. Compared with sensor A (P2228), the circuit is separate, so sensor A keeps working. P222D is the high-voltage counterpart, P222B the plausibility check.
- What you may notice
- Check engine light
- Scan tool shows a very low reading for the second barometric sensor
- Likely causes
- LikelySignal wire of sensor B shorted to ground
- Possible5 V reference to sensor B open or shorted
- RareSensor B 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 – €350
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.