P22A5NOx Sensor Heater Control Circuit High (Bank 1 Sensor 2)
- 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
- P22A5 is the opposite of P22A4: the heater control line of the rear NOx sensor on bank 1 has a short to supply voltage. The sensor module then cannot switch or regulate the heater, and the element risks running too hot or the module shuts the heater off to protect it. GM describes the check on the 3.0L LZ0 as a battery short at the heater control pin, 80 failures in 160 samples with dew point reached and supply above 9.9 V, Type B after two trips; the 2017 small diesels test the H+ supply pin of the Gen 3.0 sensor with 20 failures in 40 samples. GM bulletin 24-NA-094 lists P22A5 among codes an LZ0 software update clears on 2024 pickups. No public bulletin names a hardware fix. P22A3 is the open circuit, P22A4 the ground short, P2207 the front sensor.
- What you may notice
- Malfunction indicator lamp on after two trips
- Heater switched off, outlet NOx sensor not ready
- SCR warning on the display
- Likely causes
- LikelyHeater circuit inside the sensor shorted to supply voltage
- PossibleProbe lead or connector touching a powered conductor
- 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.