Reductant Purge Control Valve Circuit Low
The P20A2 code indicates that the powertrain control module (PCM) has detected a low 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 low circuit voltage typically points to a short to ground, open circuit, or a faulty valve. This can prevent proper DEF injection, leading to increased emissions and potential performance issues.
01. Most Common Causes
- Faulty reductant purge control valve
- Short to ground in the valve circuit
- Open circuit or damaged wiring/connectors
- Failed PCM (rare)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Reduced engine performance or power
- Increased diesel exhaust fluid consumption
- Possible failed emissions test
03. Step-by-Step Diagnosis
Step 1: Use a scan tool to confirm the code and check for related codes.
Step 2: Visually inspect the reductant purge control valve and its wiring for damage, corrosion, or loose connections.
Step 3: Test the valve's resistance with a multimeter; compare to manufacturer specs.
Step 4: Check for voltage at the valve connector with the ignition on; should be battery voltage.
Step 5: If voltage is low, check for shorts or opens in the circuit; repair as needed.
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 with this code, as it can lead to increased emissions and potential damage to the SCR system. However, short trips may be possible if the vehicle is not in limp mode.
How much does it cost to fix?▼
The cost to fix P20A2 typically ranges from $50 to $150 for parts and labor, depending on whether the valve needs replacement or just wiring repair.