Reductant Injection Valve Stuck Open Bank 2 Unit 1
The P20F7 code indicates that the reductant injection valve for Bank 2, Unit 1 is stuck open. 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 open, DEF continuously flows, potentially causing over-injection, crystallization, and damage to the SCR catalyst. This can lead to increased emissions, reduced engine performance, and illumination of the check engine light.
01. Most Common Causes
- Faulty reductant injection valve
- Electrical short or open in the valve circuit
- Contaminated or crystallized DEF blocking the valve
- Corroded or damaged wiring/connectors
02. Symptoms You Will Notice
- Check engine light on
- Reduced engine power or limp mode
- Increased DEF consumption
- Exhaust smoke or odor
03. Step-by-Step Diagnosis
Step 1: Scan for codes and verify P20F7 is present.
Step 2: Inspect the reductant injection valve and wiring for damage or corrosion.
Step 3: Test the valve resistance and compare to manufacturer specs.
Step 4: Check for DEF crystallization around the valve and clean if necessary.
Step 5: Replace the valve if it fails electrical tests or is mechanically stuck.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as it can damage the SCR system and cause reduced engine performance. You may experience limp mode.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for the part, plus labor if you have a mechanic replace it.