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U0352 Software Incompatibility With NOx Sensor C

Check engine lightUsually off
EmissionsRelevant
Drive cycleNot required
Limp modeNo

NOx sensor C is a third smart NOx sensor with its own electronics, fitted on exhaust systems with a second SCR stage, where it watches the gas behind the last catalyst. U0352 means the engine controller declines the software or calibration of this sensor, for example after a part meant for another engine or model year was fitted. No manufacturer documents U0352 publicly. GM's 2025 engine tables show that sensor C is real: the ECM expects five of its messages, logs U02A1 as Type B after more than 10 s without them and checks counter and checksum of its data (U05A8). CARB requires each emission-critical control unit to report a calibration ID and a verification number for its software. While sensor C is not accepted, the second SCR stage cannot be judged and readiness stays open. U030D and U030E cover sensors A and B.

Likely causes

NOx sensor for another engine, model year or position fitted
Engine controller updated to a level that expects another sensor software
Sensor C swapped with the sensor of another position

Symptoms

  • Check engine lamp possible, depending on the maker's rating
  • SCR or catalyst readiness does not complete
  • Code appears right after a NOx sensor replacement

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€150–900
Time0.5–2 h

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

Parts involved

nox sensor c

Related codes

U02A1U05A8U05A9U030DU030E

References: gsi.ext.gm.com, law.cornell.edu.