P22FENOx Sensor Performance - Sensing Element (Bank 1 Sensor 2)
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- P22FE tests the measuring cells of the rear NOx sensor on bank 1. On GM diesels the check runs after the engine is switched off: the sensor alters its internal pump currents so that about 1000 ppm of oxygen sits in the second cavity, and the result is compared with a reference written into its memory at the supplier. Blocked cavities lower NOx sensitivity. The 2014 Cruze diesel faults a ratio above 150 % or below 50 %, the 2016 table 200 and 20 %, the 2025 tables 140/68 % and 125/75 %, Type B or, in 2025, Type A. Volvo and Mack treat P22FE-00 as grounds to replace the outlet sensor. Software fixed it in GM PIP5615A (2018 Equinox and Terrain 1.6L diesel), 23-NA-193 (2023 Silverado 1500 3.0L) and the 5.2L DCU calibrations from Isuzu, Hino and GM.
- What you may notice
- Check engine light on
- Code sets after shutdown, so it often appears at the next start
- Driving behaviour unchanged
- Likely causes
- LikelyMeasuring cavities of the rear NOx sensor clogged or cells drifted
- PossibleECM or DEF control unit software (GM PIP5615A, 23-NA-193, Isuzu SB22-L-001)
- PossibleContamination by urea residue, oil ash or additive cleaners
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €0 – €1,100
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.