P22FE code meaning
NOx Sensor Performance - Sensing Element (Bank 1 Sensor 2)
Powertrain system Generic code P22xx codes Check engine light
What P22FE means
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.
P22FE at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor0.3 to 2 hours
- Clears after repairAfter a drive cycle
Symptoms of P22FE
- Check engine light on
- Code sets after shutdown, so it often appears at the next start
- Driving behaviour unchanged
Common causes of P22FE
- Most 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
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Nox sensor
What each part of P22FE means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 2 | Area: fuel and air metering (injector circuit). |
| FE | The exact fault in that area. |
What to do next
- Note P22FE and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P22FE
What does P22FE mean?
P22FE means "NOx Sensor Performance - Sensing Element (Bank 1 Sensor 2)". P22FE tests the measuring cells of the rear NOx sensor on bank 1. It is a generic code, so it means the same on every make.
Is it safe to drive with P22FE?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P22FE fail an emissions test?
Yes, it can. P22FE is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P22FE to fix?
Difficulty: medium. A typical repair takes 0.3 to 2 hours of work. This is a job for a workshop.
Will P22FE clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.