OBD-II code · Powertrain (generic, extended)
P22AA NOx Sensor Heater Sense Circuit Intermittent (Bank 1 Sensor 2)
The feedback line that monitors the NOx sensor heater current draw on bank 1 sensor 2 jumps or drops out intermittently — connector loose or chafed wire near the exhaust heat zone.
Is it safe to drive with P22AA?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyIntermittent connector
- Less likelyConnector with intermittent contact under vibration
- Less likelyHarness routed against vibrating component
Symptoms
- Check engine light or NOx warning on
- AdBlue/DEF level or quality warning
- Possible no-start countdown after ignore period
- Failed emissions inspection (NOx)
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Best left to a mechanic
- Typical labour
- 0.5–3 h
- Emissions test
- Likely to fail
- Parts involved
- Nox Sensor
Related codes
- P2212NOx Sensor Heater Sense Circuit Intermittent (Bank 1 Sensor 1)
- P2225NOx Sensor Heater Sense Circuit Intermittent (Bank 2)
- P22A7NOx Sensor Heater Sense Circuit Range/Performance (Bank 1 Sensor 2)
- P22A8NOx Sensor Heater Sense Circuit Low (Bank 1 Sensor 2)
- P22A9NOx Sensor Heater Sense Circuit High (Bank 1 Sensor 2)
- P22ABO2 Sensor Positive Current Control Circuit/Open (Bank 1 Sensor 2)
- P22ACO2 Sensor Positive Current Control Circuit Low (Bank 1 Sensor 2)
- P22ADO2 Sensor Positive Current Control Circuit High (Bank 1 Sensor 2)
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.