P2216NOx Sensor Circuit High Input (Bank 2)
The Bank 2 NOx sensor signal circuit is reading above its expected voltage range, usually from a short to voltage or an internal sensor failure.
Definition
The control module checks the plausibility of the Bank 2 NOx sensor signal used for SCR/DEF dosing control and catalyst monitoring. P2216 sets when the signal circuit exceeds the maximum expected threshold, indicating a short to battery voltage, connector damage, or a failed sensor element or integrated module. Consequences include an illuminated MIL, suspended closed-loop NOx control, incomplete emissions monitors, and on diesels a potential progression to SCR inducement derate if the fault is not repaired.
Common causes
- Failed NOx sensor or its integrated control module
- Signal wiring shorted to battery or reference voltage
- Connector terminal corrosion causing erratic high readings
- Water intrusion into the sensor module
- Exhaust leak upstream of the sensor skewing readings
- Harness damage from heat or rubbing
Common misdiagnoses
- SCR catalyst
- DEF doser
- Bank 1 sensor replaced instead of Bank 2
- ECM/PCM replacement without circuit testing
Troubleshooting steps
1.Verify which sensor is affected
Use service information to positively identify the Bank 2 sensor position before starting diagnosis.
2.Review live NOx data
A Bank 2 reading pegged high or frozen while Bank 1 responds normally confirms a sensor or circuit fault rather than an actual NOx problem.
3.Inspect wiring for shorts to power
Check for melted or chafed insulation where the harness runs near the exhaust or crosses other powered circuits.
4.Check for exhaust leaks ahead of the sensor
Repair any leaks that admit ambient air, which can drive the sensor's readings implausibly high.
5.Replace the NOx sensor if wiring is verified
Fit an OE sensor, clear the code, and complete the manufacturer's drive cycle to confirm monitor completion.