Powertrain, generic (extended)

P222C Barometric Pressure Sensor B Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

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.

Likely causes

Signal wire of sensor B shorted to ground
5 V reference to sensor B open or shorted
Sensor B internally defective

Symptoms

  • Check engine light
  • Scan tool shows a very low reading for the second barometric sensor

Repair estimate

DifficultyMediumDIY possible
Parts and labour€40–350
Time0.5–2 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

barometric pressure sensorsensor wiring

Related codes

P222AP222BP222DP222EP2228

References: gsi.ext.gm.com, gsi.ext.gm.com, gsi.ext.gm.com.