P2201NOx Sensor Circuit Range/Performance (Bank 1 Sensor 1)
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- Here the upstream NOx sensor on bank 1 is electrically intact, yet its reading is not believable. Manufacturers test this in different ways. VW's 2014 Touareg TDI compares the reading with modelled engine-out NOx (deviation beyond 60 percent), checks a slow fall from 100 to 60 percent (over 4.5 s) and an offset outside +50/-30 ppm. Ford runs a self-test after shutdown and flags an offset above about 20 ppm low or 40 ppm high. GM's 3.0L Duramax (LZ0) watches internal pump-current stability, Type B over two trips. Ford TSBs 24-2136/24-2148 fix 2020-2023 6.7L trucks with a new sensor and software; Volvo and Mack warn that the code often results from another fault and ask for a conversion test first. P229F is the downstream twin.
- What you may notice
- Malfunction indicator lamp on
- Often stored together with SCR efficiency codes such as P20EE
- Increased AdBlue consumption or SCR warning
- Likely causes
- LikelyAged or poisoned NOx sensing element with offset or slow response
- PossibleExhaust leak upstream of the sensor letting in outside air
- PossibleFault elsewhere (EGR, fuelling, DEF dosing) that shifts real NOx output
- RareControl software calibration (Ford 6.7L 2020-2023, TSB 24-2136/24-2148)
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €100 – €1,100
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.