NOx Sensor Heater Circuit Low Bank 2
The P2223 code indicates that the powertrain control module (PCM) has detected a low voltage condition in the heater circuit of the nitrogen oxide (NOx) sensor on Bank 2. This sensor is typically located downstream of the selective catalytic reduction (SCR) system in diesel vehicles. The heater is essential for the sensor to reach operating temperature quickly and provide accurate readings. A low circuit condition suggests a short to ground, open circuit, or failed sensor, which can lead to incorrect NOx readings and affect emissions control.
1. Most Common Causes
- Faulty NOx sensor (Bank 2)
- Open or shorted heater circuit wiring
- Blown fuse or relay for NOx sensor heater
- Corroded or damaged connector
- PCM failure (rare)
2. Symptoms You Will Notice
- Check Engine Light illuminated
- Failed emissions test
- Reduced fuel economy
- Possible limp mode activation
- Excessive diesel exhaust fluid (DEF) consumption
3. Step-by-Step Diagnosis
Step 1: Scan for codes and verify P2223 is present. Check freeze frame data.
Step 2: Visually inspect the NOx sensor connector and wiring for damage, corrosion, or loose connections.
Step 3: Use a multimeter to test the heater circuit resistance (typically 2-10 ohms) and voltage supply (should be battery voltage with key on).
Step 4: If wiring and voltage are OK, replace the NOx sensor on Bank 2.
Step 5: Clear codes and test drive to confirm repair.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
You can drive short distances, but the vehicle may enter limp mode and fail emissions. Prolonged driving can cause damage to the SCR system.
How much does it cost to fix?▼
Replacing the NOx sensor typically costs $200-$600 including parts and labor. Diagnosis may add $100-$150.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.