Powertrain, generic (extended)

P22FE NOx Sensor Performance - Sensing Element (Bank 1 Sensor 2)

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

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.

Likely causes

Measuring cavities of the rear NOx sensor clogged or cells drifted
ECM or DEF control unit software (GM PIP5615A, 23-NA-193, Isuzu SB22-L-001)
Contamination by urea residue, oil ash or additive cleaners

Symptoms

  • Check engine light on
  • Code sets after shutdown, so it often appears at the next start
  • Driving behaviour unchanged

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€0–1,100
Time0.3–2 h

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

Parts involved

nox sensor

Related codes

P22FBP22FCP22FDP229FP23C1

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