P229ENOx Sensor Circuit (Bank 1 Sensor 2)
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- 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.
- What you may notice
- Malfunction indicator lamp on
- No valid downstream NOx value in live data
- SCR warning; catalyst efficiency check cannot complete
- Likely causes
- LikelyInternal failure of the outlet NOx probe or its control unit
- PossibleDamaged lead between probe and sensor control unit (heat, chafing)
- PossibleWater or corrosion in the sensor connector
- RareEngine control software needing an update (Nissan Titan XD 2016, NTB16-048)
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Often possible to do yourself.Typical cost: €150 – €1,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.