NOx Sensor Heater Control Circuit Low Bank 2
The NOx sensor heater control circuit on Bank 2 is detecting a low voltage condition, meaning the heater isn't receiving sufficient power to warm the sensor properly. The NOx sensor requires heating to function correctly for accurate emissions monitoring, so this fault will cause the sensor to provide inaccurate readings and trigger emissions test failures.
What You Might Notice
- Check Engine Light illuminated
- Failed emissions test
- Intermittent check engine light flashing
- Reduced engine performance
- Increased exhaust emissions
Most Common Causes
- 1
Faulty NOx sensor heater element
The heater element inside the NOx sensor has failed or burned out, preventing it from generating heat and drawing excessive current, which causes a low voltage condition in the control circuit.
- 2
Corroded or damaged wiring connectors
The connector pins for the NOx sensor heater circuit are corroded, loose, or damaged, creating poor electrical contact and voltage drop in the circuit.
- 3
Broken heater control relay
The relay controlling power to the NOx sensor heater is defective or stuck open, preventing adequate current from reaching the heater element.
- 4
Wiring harness damage or short to ground
The heater control circuit wiring is damaged, frayed, or shorted to ground, causing voltage loss before reaching the sensor heater.
How to Diagnose It
- 1
Check Faulty NOx sensor heater element — The heater element inside the NOx sensor has failed or burned out, preventing it from generating heat and drawing excessive current, which causes a low voltage condition in the control circuit.
- 2
Check Corroded or damaged wiring connectors — The connector pins for the NOx sensor heater circuit are corroded, loose, or damaged, creating poor electrical contact and voltage drop in the circuit.
- 3
Check Broken heater control relay — The relay controlling power to the NOx sensor heater is defective or stuck open, preventing adequate current from reaching the heater element.
- 4
Check Wiring harness damage or short to ground — The heater control circuit wiring is damaged, frayed, or shorted to ground, causing voltage loss before reaching the sensor heater.
How to Fix It
- 1
Replace NOx sensor
Remove the faulty NOx sensor on Bank 2 and install a new sensor with a functioning heater element. Disconnect the electrical connector, unbolt the sensor from the exhaust manifold, and reverse the process with the new part.
- 2
Inspect and repair wiring connections
Locate the NOx sensor heater control connector and wiring. Check for corrosion, moisture, or loose pins. Clean corroded connectors with contact cleaner, tighten any loose connections, and repair any damaged wiring with proper splices or replacement segments.
- 3
Replace heater control relay
Locate the relay controlling the NOx sensor heater circuit in the engine bay fuse/relay box. Remove the defective relay and install a new one with matching specifications. Verify the relay position and amperage rating before installation.
- 4
Clear diagnostic code after repair
After completing repairs, use a diagnostic scanner to clear the P2219 code and perform a test drive to ensure the code does not return, confirming the fault has been resolved.
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