P2221NOx Sensor Heater Sense Circuit (Bank 2)
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- Alongside the heater drive, a NOx sensor has a sense path that tells the electronics how the heater is really behaving, usually by measuring its resistance, which tracks cell temperature. P2221 reports a general fault in that sense circuit on the bank 2 sensor. Public documentation exists only for the bank 1 code P2208: GM's 3.0L LZ0 checks the separate HTemp pin for an open load, 80 failures in 160 samples at over 11 V, Type A with the MIL after one trip, and notes that its Continental sensors debounce electrical faults internally for 1.5 s. No manufacturer lists the bank 2 version. Without valid feedback the sensor cannot regulate its temperature. P2222 to P2225 are the specific sense faults.
- What you may notice
- Malfunction indicator lamp on
- Bank 2 NOx sensor not ready
- Likely causes
- LikelyFault in the heater measurement of the bank 2 sensor
- PossibleOpen sense conductor between probe and sensor module
- RareCorrosion in the sensor connector
- 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: €150 – €1,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.