Powertrain, generic (extended)

P229E NOx Sensor Circuit (Bank 1 Sensor 2)

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P229E is the basic electrical fault of the second NOx sensor on bank 1, the one behind the SCR catalyst that shows how much NOx survives conversion. Its attached control unit checks the probe lines and passes the result to the engine computer over CAN. GM's 6.6L Duramax (LML) sets the code as Type A when an open or shorted status keeps arriving longer than 10 s, or 0.5 s in a later calibration. Ford's 3.0L and 6.7L diesels use it for shorts and opens on the Vs, COM, Ip1 and Ip2 lines and for a failed internal self-test of the sensor processor; VW's 2014 Touareg TDI for an error message or a validity ratio above 0.5. Volvo and Mack replace the outlet sensor, and Nissan bulletin NTB16-048 does the same on the 2016 Titan XD, adding an ECM update. P2200 is the front sensor.

Likely causes

Internal failure of the outlet NOx probe or its control unit
Damaged lead between probe and sensor control unit (heat, chafing)
Water or corrosion in the sensor connector
Engine control software needing an update (Nissan Titan XD 2016, NTB16-048)

Symptoms

  • Malfunction indicator lamp on
  • No valid downstream NOx value in live data
  • SCR warning; catalyst efficiency check cannot complete

Repair estimate

DifficultyMediumDIY possible
Parts and labour€150–1,000
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

P229FP22A0P22A1P22A2P220BP2200U029E

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