P2202NOx Sensor Circuit Low (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
- 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.
- What you may notice
- Malfunction indicator lamp on
- Live data shows a negative NOx value upstream
- SCR dosing may switch to a fallback strategy
- Likely causes
- LikelyNOx sensing element drifted low or internally faulty
- PossibleEngine software anomaly (GM 3.0L LZ0 2024, bulletin 24-NA-094)
- RareDamaged probe lead or connector between element and sensor module
- 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: €0 – €1,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.