Reductant Injection Air Pressure Leakage
The P20CA code indicates a leak in the reductant injection air pressure system, which is part of the Selective Catalytic Reduction (SCR) system used to reduce NOx emissions. The system uses compressed air to inject diesel exhaust fluid (DEF) into the exhaust stream. A leak can cause insufficient DEF injection, leading to increased emissions and potential damage to the SCR catalyst. Common causes include cracked air lines, loose connections, or a faulty air pressure sensor.
01. Most Common Causes
- Cracked or damaged air supply lines
- Loose or disconnected air hose fittings
- Faulty reductant injection air pressure sensor
- Blocked or restricted air filter in the system
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Reduced engine performance or power
- Increased diesel exhaust fluid consumption
- Failed emissions test
03. Step-by-Step Diagnosis
Step 1: Use an OBD2 scanner to confirm the P20CA code and check for any related codes.
Step 2: Visually inspect all air lines and connections from the air pump to the reductant injector for cracks, leaks, or disconnections.
Step 3: Test the reductant injection air pressure sensor using a multimeter to ensure it is within manufacturer specifications.
Step 4: Check the air filter in the reductant injection system for clogs and replace if necessary.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive with this code 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 to fix a P20CA code typically ranges from $50 to $150 for parts and labor, depending on the cause. Replacing a cracked air line or sensor is usually inexpensive.