NOx Sensor Heater Control Circuit Low Bank 2
The P2219 code indicates that the powertrain control module (PCM) has detected a low voltage condition in the heater control circuit of the nitrogen oxide (NOx) sensor on Bank 2. This sensor is part of the selective catalytic reduction (SCR) system used to reduce emissions. The heater is essential for the sensor to reach operating temperature quickly, especially during cold starts. A low circuit voltage suggests a short to ground, open circuit, or a faulty sensor, which can lead to inaccurate NOx readings and potential emissions non-compliance.
01. Most Common Causes
- Faulty NOx sensor (Bank 2)
- Open or shorted heater circuit wiring
- Blown fuse or relay for NOx sensor heater
- Corroded or loose connector at sensor
- Failed PCM (rare)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Increased emissions
- Possible reduced engine performance
- Failed emissions test
03. Step-by-Step Diagnosis
Step 1: Use a scan tool to confirm P2219 and check for related codes.
Step 2: Visually inspect the NOx sensor connector and wiring for damage, corrosion, or loose connections.
Step 3: Measure voltage at the heater circuit (typically 12V) with key on, engine off. If low, check fuses and relays.
Step 4: Test the NOx sensor heater resistance with a multimeter; compare to manufacturer specs.
Step 5: If all else is good, replace the NOx sensor on Bank 2.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
You can drive short distances, but the vehicle may fail emissions and could enter limp mode. Prolonged driving may damage the SCR system.
How much does it cost to fix?▼
Typically $50-$150 for diagnosis and parts, plus labor. Sensor replacement can cost $200-$400 total.