What it means
NOx Sensor Circuit High (Bank 2): the signal voltage is above the expected range. Often an open circuit or a short to supply voltage.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The bank 2 NOx sensor sends an electrical signal to the emissions control module. P2216 sets when that signal rises above the expected range, which can be caused by an open signal path or an unintended connection to supply voltage.
Common causes
Most likely first.
- Open signal line
- Connector pins corroded - high contact resistance
- Supply wire pinched against B+ source
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)
How to diagnose it
- Save freeze-frame data and review live bank 2 NOx sensor status to confirm the high signal and its operating conditions.
- Inspect the bank 2 sensor connector for a loose or backed-out pin, corrosion, or heat damage.
- Check the bank 2 signal harness for breaks, chafing, or contact with a power wire.
- Test signal circuit continuity and check for a short to voltage using the wiring diagram and the manufacturer's specification.
- If the circuit is intact, test the bank 2 NOx sensor and its power and ground connections according to the manufacturer's procedure.
Common fixes
- Repair a loose or damaged bank 2 sensor connector.
- Repair an open signal wire or short to supply voltage.
- Restore a poor bank 2 sensor circuit connection.
- Replace the bank 2 NOx sensor if its output remains high with a verified circuit.
Can I keep driving?
Brief driving may be possible if the vehicle runs normally, but the high signal can leave NOx emissions unmonitored or incorrectly controlled. Limit driving and respond promptly to an AdBlue/DEF warning or start countdown.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.