Diagnostic article Generic OBD-II
P22B7: NOx sensor 2 oxygen signal above its reporting ceiling
P22B7 checks for an oxygen concentration signal above the documented physical-range ceiling.
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Documented application
2025 GM 25OBDG04B diagnostic parameter file; the cited monitor is documented, but individual vehicle, engine and calibration applicability has not been established.
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.
P22B7 carries the generic label oxygen-sensor pumping-current trim circuit high. The GM monitor explains it as an oxygen signal exceeding its physical maximum, with a threshold above 29.00%. Its context is bank 1 sensor 2 and the NOx-sensor oxygen signal family, rather than a specified external-wire voltage.
The actual check
The source lists 100 failures out of 200 samples on a 25 ms task and Type B, two-trip reporting. It names engine running, suitable system voltage, a fully operative sensor, exhaust pressure and no active exhaust brake among the secondary conditions. Several numerical enable cells are blank in this row, so neighboring-code values should not be silently substituted.
What the result can establish
An above-ceiling oxygen signal is evidence that the reported measurement is outside this monitor's accepted range. It does not by itself identify a failed catalyst, establish a real exhaust oxygen concentration, or tell a technician which terminal has high voltage.
For a meaningful review, retain the oxygen-percent parameter and the sensor's validity state at the event. Then confirm that the relevant monitor completed after diagnosis. A normal NOx concentration alone does not verify this oxygen check, and a test performed while exhaust-brake or sensor-readiness conditions prevent monitoring is inconclusive. Vehicle-specific service information is needed for the omitted enable values and any electrical testing.
Source and application limits
This explanation covers the cited 2025 GM monitor. Confirm the vehicle and calibration in its service information before applying these limits; inclusion in this file does not establish model compatibility. GM diagnostic parameters, PDF page 1438.
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
O2 Sensor Pumping Current Trim Circuit High Bank 1 Sensor 2
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