P2223
NOx Sensor Heater Sense Circuit Low Bank 2
Emissions / NOx sensor
Generic OBD-II
Medium
What it means
P2223 means the ECM sees low voltage on the heater-sense circuit of the bank 2 NOx sensor. The heater brings the sensor up to operating temperature so it can read accurately; a fault here keeps the emissions monitor from completing. The engine drives normally, but the sensor, its heater, or the wiring needs attention.
Medium
Can I keep driving? The engine runs normally; this is a NOx-sensor heater circuit fault that mainly affects emissions monitoring, so you can drive while arranging repair.
Common symptoms
What you'll notice
- Check-engine light on
- NOx / emissions readiness monitor won't complete
- Possible emissions-test failure
- On some diesels, SCR warning messages
Common causes
Most likely first
- Faulty NOx sensor heater (bank 2)Likely
- Low voltage or high resistance in the heater-sense circuit wiringCommon
- Poor or corroded connector at the sensorCommon
- Open or short pulling the sense signal lowLess often
How to diagnose & fix
Work through it in order
- Inspect the NOx sensor heater connector and wiring for corrosion or damage.
- Check the heater-sense circuit voltage and ground.
- Compare NOx sensor live data / heater status on a scan tool.
- Replace the NOx sensor if its integrated heater circuit is out of range.
- Clear and complete a drive cycle to confirm.
FAQ
Quick answers
Is it safe to drive with P2223?+
Yes, mechanically. It affects the NOx sensor's heater and therefore emissions monitoring, not how the engine runs, so you can drive while arranging a repair.
Can I just clear P2223?+
It returns while the heater circuit is faulty, and the emissions monitor won't complete until the sensor or wiring is repaired.
Related codes
Often seen with P2223
Read & clear P2223 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX