NOx Sensor Heater Sense Circuit Low Bank 2
P2223 indicates the NOx (nitrogen oxide) sensor heater circuit on Bank 2 is detecting a voltage that is too low. The engine control module monitors this heater circuit to ensure the NOx sensor operates at the correct temperature for accurate emissions readings. A low voltage condition suggests a wiring issue, connector problem, or sensor heater failure.
What You Might Notice
- Check Engine Light illuminated
- Increased emissions readings
- Reduced fuel economy
- Engine stalling or hesitation
- Rough idle conditions
Most Common Causes
- 1
NOx Sensor Heater Element Failure
The internal heater element in the NOx sensor has failed or is weakened, preventing proper heating of the sensor. This results in insufficient voltage being supplied to the heater circuit.
- 2
Wiring or Connector Issue
Corroded, damaged, or loose wiring in the NOx sensor heater circuit prevents proper voltage delivery. Check for water intrusion, corrosion, or bent connector pins at the sensor connection.
- 3
ECM or Relay Malfunction
The engine control module or the relay controlling the NOx sensor heater circuit is faulty, preventing adequate voltage from reaching the sensor heater.
- 4
Blown Fuse or Open Circuit
The fuse protecting the NOx sensor heater circuit has blown, or an open circuit exists in the wiring path from the ECM to the sensor.
How to Diagnose It
- 1
Check NOx Sensor Heater Element Failure — The internal heater element in the NOx sensor has failed or is weakened, preventing proper heating of the sensor. This results in insufficient voltage being supplied to the heater circuit.
- 2
Check Wiring or Connector Issue — Corroded, damaged, or loose wiring in the NOx sensor heater circuit prevents proper voltage delivery. Check for water intrusion, corrosion, or bent connector pins at the sensor connection.
- 3
Check ECM or Relay Malfunction — The engine control module or the relay controlling the NOx sensor heater circuit is faulty, preventing adequate voltage from reaching the sensor heater.
- 4
Check Blown Fuse or Open Circuit — The fuse protecting the NOx sensor heater circuit has blown, or an open circuit exists in the wiring path from the ECM to the sensor.
How to Fix It
- 1
Replace NOx Sensor
Remove the faulty NOx sensor on Bank 2 and install a new OEM or quality replacement sensor with proper heater element. Clear the code after installation and verify proper operation.
- 2
Inspect and Repair Wiring
Locate the NOx sensor heater circuit wiring harness, inspect for corrosion, damage, or loose connections. Repair or replace damaged wiring and ensure all connector pins are clean and properly seated.
- 3
Check and Replace Fuse
Locate the fuse protecting the NOx sensor heater circuit in the fuse box and check for a blown fuse. Replace with the correct amperage fuse if blown.
- 4
Test ECM and Relay
If wiring, connectors, and sensor have been verified good, test the relay and ECM output voltage to the heater circuit with a multimeter. Replace the relay or have the ECM diagnosed by a professional if voltage is not present.
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