Reductant Injection Valve Stuck Closed Bank 1 Unit 1
The P208E code indicates that the reductant injection valve for Bank 1 Unit 1 is stuck in the closed position. 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. When stuck closed, DEF cannot be injected, leading to increased emissions and potential performance issues. The code is triggered when the powertrain control module (PCM) detects that the valve is not opening as commanded.
01. Most Common Causes
- Faulty reductant injection valve
- Wiring or connector issues in the valve circuit
- DEF crystallization or contamination blocking the valve
- PCM software or hardware failure
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Reduced engine performance or power
- Increased NOx emissions
- Possible DEF warning light or message
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 injection valve and its wiring for damage or corrosion.
Step 3: Test the valve's resistance and operation using a multimeter or scan tool bi-directional control.
Step 4: Check for DEF crystallization or blockage in the valve or lines.
Step 5: If necessary, replace the valve and clear the code.
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 $50 to $150 for the part, plus labor if done by a mechanic. DIY replacement can save on labor costs.