NOx Sensor Heater Sense Circuit Bank 1
The P2208 code indicates a malfunction in the heater sense circuit of the NOx sensor on Bank 1. The NOx sensor measures nitrogen oxide levels in the exhaust and requires a heater to reach operating temperature quickly. The Engine Control Module (ECM) monitors the current draw of the heater circuit; if it detects an open, short, or out-of-range condition, it sets this code. This can lead to increased emissions and potential drivability issues.
01. Most Common Causes
- Faulty NOx sensor heater element
- Open or shorted wiring in the heater circuit
- Corroded or damaged connector at the NOx sensor
- Failed ECM (rare)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Failed emissions test
- Possible reduced fuel economy
- Possible engine performance issues
03. Step-by-Step Diagnosis
Step 1: Scan for additional codes and freeze frame data.
Step 2: Visually inspect the NOx sensor connector and wiring for damage or corrosion.
Step 3: Measure resistance of the heater circuit at the sensor connector (typically 2-10 ohms).
Step 4: Check for battery voltage and ground at the sensor connector with the ignition on.
Step 5: If wiring and voltage are okay, replace the NOx sensor.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
Yes, but the vehicle may fail emissions testing and fuel economy could decrease. It's best to repair promptly.
How much does it cost to fix?▼
Typically $200-$600 including parts and labor, depending on vehicle make and sensor accessibility.