OBD-II code · Powertrain (generic, extended)
P224A NOx Sensor Heater Resistance (Bank 1 Sensor 1)
The measured heater element resistance of the NOx sensor on bank 1 sensor 1 is outside the calibrated range. Used as a sensor-element health check.
Is it safe to drive with P224A?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyHeater element aged
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
- 1–3 h
- Emissions test
- Likely to fail
- Parts involved
- Nox Sensor
Related codes
- P224BNOx Sensor Heater Resistance (Bank 1 Sensor 2)
- P2247O2 Sensor Reference Voltage Circuit (Bank 2 Sensor 1)
- P2248O2 Sensor Reference Voltage Circuit Range/Performance (Bank 2 Sensor 1)
- P2249O2 Sensor Reference Voltage Circuit Low (Bank 2 Sensor 1)
- P224CAlternative Fuel Tank Shutoff Valve A Control Circuit/Open
- P224DAlternative Fuel Tank Shutoff Valve A Control Circuit Performance/Stuck Off
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.