P2204NOx Sensor Circuit Intermittent (Bank 1 Sensor 1)
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- P2204 describes an upstream NOx sensor on bank 1 whose signal path works most of the time but keeps dropping out. Smart NOx sensors report the state of their measuring circuit (open wire, short or no error) to the engine computer over CAN; when such fault messages come and go faster than a steady circuit fault would allow, this code fits. No manufacturer publicly documents thresholds for P2204, so the logic is calibration-specific; CARB generally requires continuous detection of circuit-continuity faults on NOx sensors. Look for loose pins, heat-damaged cable near the exhaust and water in the connector. P2200 is the steady circuit fault, P2202/P2203 a value out of range. Expect a MIL and SCR warnings that may disappear and return.
- What you may notice
- Malfunction indicator lamp on, sometimes going out again
- NOx value in live data dropping out briefly
- SCR warning that comes and goes
- Likely causes
- LikelyLoose or corroded terminals at the NOx sensor connector
- PossibleHarness near the exhaust damaged by heat or vibration
- PossibleIntermittent internal fault in the 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: €50 – €900
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.