NOx Sensor Heater Sense Circuit High Bank 2
P2224 indicates the NOx sensor heater sense circuit on Bank 2 is reading a voltage that is too high. The engine control module continuously monitors this circuit to ensure the NOx sensor heater operates properly for accurate emissions control. This fault prevents the sensor from reaching optimal operating temperature, affecting its ability to measure nitrogen oxide levels correctly.
What You Might Notice
- Check engine light (MIL) illuminated
- Reduced fuel economy
- Engine hesitation or inconsistent idle
- Potential rough running conditions
- Failed emissions test
Most Common Causes
- 1
NOx Sensor Heater Circuit Wiring Issue
Open, short, or corroded wiring in the NOx sensor heater sense circuit. Corrosion from moisture or road salt can increase resistance and cause high voltage readings.
- 2
Faulty NOx Sensor Heater
The heating element within the NOx sensor has failed or is malfunctioning, causing abnormal resistance in the circuit and triggering the high voltage fault.
- 3
Defective NOx Sensor
The NOx sensor itself may be defective or have internal damage affecting the heater sense circuit signal, resulting in out-of-range voltage readings.
- 4
Engine Control Module (ECM) or Connector Issues
A faulty ECM connection, corroded connector pins, or a defective ECM can cause improper voltage readings on the NOx sensor heater circuit.
How to Diagnose It
- 1
Check NOx Sensor Heater Circuit Wiring Issue — Open, short, or corroded wiring in the NOx sensor heater sense circuit. Corrosion from moisture or road salt can increase resistance and cause high voltage readings.
- 2
Check Faulty NOx Sensor Heater — The heating element within the NOx sensor has failed or is malfunctioning, causing abnormal resistance in the circuit and triggering the high voltage fault.
- 3
Check Defective NOx Sensor — The NOx sensor itself may be defective or have internal damage affecting the heater sense circuit signal, resulting in out-of-range voltage readings.
- 4
Check Engine Control Module (ECM) or Connector Issues — A faulty ECM connection, corroded connector pins, or a defective ECM can cause improper voltage readings on the NOx sensor heater circuit.
How to Fix It
- 1
Inspect and Repair Wiring and Connectors
Visually inspect the NOx sensor heater wiring and connectors for corrosion, damage, or loose connections. Clean corroded connectors with electrical contact cleaner or replace damaged wiring. Ensure all connections are secure.
- 2
Test NOx Sensor Heater Circuit Voltage
Use a multimeter to test the voltage at the NOx sensor heater circuit with the key on and engine off. Compare readings to manufacturer specifications to confirm the circuit is reading high.
- 3
Replace NOx Sensor
If wiring is intact and voltage testing confirms the fault, replace the NOx sensor on Bank 2. This is the most common solution for this code on diesel and some gasoline engines.
- 4
Check or Replace ECM and Test Again
If the above steps do not resolve the issue, have the ECM connector inspected for corrosion or damage. If ECM connector is faulty, repair or replace as needed. If all else fails, the ECM may require replacement.
Need a deeper diagnosis?
Search for related repair guides or browse by system.