Diagnostic article Generic OBD-II
P222C: Why barometric sensor B circuit-low can be a digital count limit
Read P222C as a raw digital range test in the documented GM sensor system, rather than an atmospheric-pressure diagnosis.
Read before applying this article
Documented application
2025 GM 25OBDG07A Part 2 monitor tables only; model, engine and transmission applicability are not established by the unresolved application-matrix filename join.
The code alone does not identify a failed part or establish that a vehicle is safe to drive. Confirm the vehicle, reporting module and applicable service procedure.
P222C is a low-range check for the bank 2 barometric-pressure sensor in this GM table. Although the generic name says circuit low, the compared value is raw digital sensor data, not a pressure value expressed in kPa and not an external test-pin voltage.
A digital boundary is not low atmospheric pressure
The failure criterion is a raw count of one or less. The row lists a fifty-millisecond test period and requires ignition on. It also excludes the specified HFM chip heating/standby status and refers to inhibition tables.
These details matter because a very low raw code may indicate that the data is outside its valid representational range. It should not be treated as a trustworthy report that ambient pressure has physically fallen to an extreme value.
Separate range failure from physical plausibility
The same source provides a distinct P222B family of physical-range and cross-check diagnostics. Those ask whether pressure information makes sense; P222C addresses the raw digital lower boundary before such an interpretation can be trusted.
The useful evidence includes raw data, sensor status and whether the check was enabled. If a scan tool only displays a converted pressure, establish how invalid digital values are represented before drawing an atmospheric conclusion. The summary does not give a connector pinout or identify a failed sensor versus a data-path problem. Its count threshold belongs to this digital sensor implementation and must not be converted into a universal analogue-voltage specification.
Source and scope
2025 GM 25OBDG07A Part 2 monitor tables only; model, engine and transmission applicability are not established by the unresolved application-matrix filename join. These are documented monitor criteria, not a universal repair procedure. GM PDF, physical page 878 · GM PDF, physical page 879 · GM PDF, physical page 880.
Article source documents
Source checks describe how the text was prepared; they do not certify a diagnosis or confirm compatibility with every vehicle using this code.
Original code reference
Dictionary definition
Barometric Pressure Sensor B Circuit Low
This definition retains its original catalog scope. The article above is limited to its explicitly documented application.
Reference scope
Generic OBD-II definition.
A manufacturer label does not establish the model, year, engine or module to which a diagnosis applies. Read the safety and diagnostic limits.
Definition source
- DTC Database: pinned community code definitions
Source checked · MIT