Powertrain, generic (extended)

P2202 NOx Sensor Circuit Low (Bank 1 Sensor 1)

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

P2202 means the raw NOx value sent by the upstream sensor on bank 1 has dropped below the lowest figure a working sensor can report. Since the probe talks over CAN, the check concerns the transmitted value rather than a wire voltage. GM's Duramax diesels (6.6L LML and 3.0L LZ0) use a limit of minus 90 ppm, the LZ0 as Type B after two trips with dew point reached and supply in range; VW's 2014 Touareg TDI uses minus 105 ppm. GM bulletin 24-NA-094 lists P2202 among codes cured by an LZ0 software update on 2024 Silverado and Sierra 1500 pickups. A clearly negative value usually points to a drifting element or an internal sensor error. P2203 is the upper limit; P22A0 the same for sensor 2.

Likely causes

NOx sensing element drifted low or internally faulty
Engine software anomaly (GM 3.0L LZ0 2024, bulletin 24-NA-094)
Damaged probe lead or connector between element and sensor module

Symptoms

  • Malfunction indicator lamp on
  • Live data shows a negative NOx value upstream
  • SCR dosing may switch to a fallback strategy

Repair estimate

DifficultyMediumDIY possible
Parts and labour€0–1,000
Time0.5–2.5 h

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

Parts involved

nox sensornox sensor wiring

Related codes

P2200P2201P2203P2204P22A0P2215

References: gsi.ext.gm.com, gsi.ext.gm.com, static.nhtsa.gov, static.nhtsa.gov.