P22A3NOx Sensor Heater Control Circuit/Open (Bank 1 Sensor 2)
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- The ceramic element of a NOx sensor measures only after its built-in heater has brought it to several hundred degrees. P22A3 reports a break on the heater control side of the rear sensor on bank 1, behind the SCR catalyst. GM's 6.6L LML sets it when the sensor reports an open heater over CAN longer than 10 s, Type A. On the 3.0L LZ0 the heater control pin is tested for a missing load (80 failures in 160 samples), on the 2017 small diesels the H+ supply pin of the Gen 3.0 sensor; both Type A, so the MIL comes on after one trip. Volvo and Mack read P22A3-13 as a probable outlet sensor failure, and GM bulletin 24-NA-094 lists the code for an LZ0 software update. P22A4 and P22A5 are shorts, P22A6 the heater sense line, P2205 the front sensor.
- What you may notice
- Malfunction indicator lamp on after one trip
- Outlet NOx sensor never reports ready
- SCR warning on the display
- Likely causes
- LikelyHeater element in the outlet NOx probe burnt through
- PossibleBroken conductor between probe and sensor module
- RareSoftware anomaly (GM 3.0L LZ0 2024, bulletin 24-NA-094)
- 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.