Reductant Purge Control Valve Circuit High
The P20A3 code indicates that the powertrain control module (PCM) has detected a high voltage condition in the reductant purge control valve circuit. This valve is part of the selective catalytic reduction (SCR) system, which injects diesel exhaust fluid (DEF) into the exhaust stream to reduce NOx emissions. A high voltage signal suggests a short to power, open circuit, or a faulty valve, potentially causing improper DEF dosing and increased emissions.
01. Most Common Causes
- Faulty reductant purge control valve
- Short to power in the valve circuit
- Open or damaged wiring/connector
- Failed PCM (rare)
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 codes and record freeze frame data.
Step 2: Visually inspect the reductant purge control valve and its wiring for damage or corrosion.
Step 3: Test the valve's resistance with a multimeter (specs vary by vehicle).
Step 4: Check for voltage at the valve connector with key on; should be battery voltage or as per manufacturer specs.
Step 5: If voltage is high or erratic, repair short to power or replace valve.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is generally not recommended to drive long distances, as the vehicle may enter limp mode and emissions will be elevated. Short trips to a repair shop are acceptable.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for diagnosis and repair, including parts and labor. The valve itself may cost $30-$80.