Reductant Injection Air Pressure Control Valve Circuit/Open
The P20A6 code indicates a problem in the reductant injection air pressure control valve circuit, which is part of the Selective Catalytic Reduction (SCR) system. This valve regulates air pressure to assist in injecting diesel exhaust fluid (DEF) into the exhaust stream. An open circuit means there is a break in the electrical path, preventing the valve from functioning. This can lead to insufficient DEF injection, causing increased NOx emissions and potential damage to the SCR system.
01. Most Common Causes
- Faulty reductant injection air pressure control valve
- Open or shorted wiring in the valve circuit
- Corroded or damaged electrical connectors
- Blown fuse or relay in the SCR system
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Reduced engine performance or power
- Increased exhaust emissions
- Possible DEF system warning messages
03. Step-by-Step Diagnosis
Step 1: Use an OBD2 scanner to confirm the code and check for related codes.
Step 2: Visually inspect the wiring and connectors for damage, corrosion, or loose connections.
Step 3: Test the valve's resistance with a multimeter; compare to manufacturer specs.
Step 4: Check for power and ground at the valve connector with the ignition on.
Step 5: If wiring is intact, replace the reductant injection air pressure control valve.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive for extended periods, as it can lead to increased emissions and potential damage to the SCR system. The vehicle may enter limp mode to protect the engine.
How much does it cost to fix?▼
The cost typically ranges from $150 to $400, including parts and labor. The valve itself costs $50-$150, and labor adds $100-$250 depending on the shop.