Reductant Quality Sensor Circuit Malfunction
The P206A code indicates a problem with the reductant quality sensor circuit, which monitors the quality of diesel exhaust fluid (DEF) in selective catalytic reduction (SCR) systems. This sensor detects contamination or incorrect concentration of DEF, and a circuit fault can lead to improper emissions control, potentially causing increased NOx emissions and triggering the check engine light.
01. Most Common Causes
- Faulty reductant quality sensor
- Open or shorted wiring in the sensor circuit
- Corroded or damaged connector
- Contaminated or incorrect DEF fluid
02. Symptoms You Will Notice
- Check engine light illuminated
- Reduced engine performance or limp mode
- Increased diesel exhaust fluid consumption
- Failed emissions test
03. Step-by-Step Diagnosis
Step 1: Scan for additional codes and freeze frame data.
Step 2: Visually inspect the reductant quality sensor and its wiring for damage or corrosion.
Step 3: Test the sensor circuit voltage and resistance with a multimeter per manufacturer specs.
Step 4: Check DEF fluid quality and level; replace if contaminated or incorrect.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as it can lead to reduced engine performance, increased emissions, and potential damage to the SCR system. Limp mode may activate.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for diagnosis and sensor replacement, but can be higher if wiring repairs or DEF system flushing is needed.