P2057: Reductant Injection Valve Circuit Low Bank 2 Unit 2
The P2057 code indicates that the powertrain control module (PCM) has detected a low voltage condition in the reductant injection valve circuit for Bank 2, Unit 2. 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 signal suggests a short to ground, open circuit, or faulty valve, potentially leading to increased emissions and triggering the check engine light.
01. Most Common Causes
- Faulty reductant injection valve
- Open or shorted wiring in the valve circuit
- Corroded or damaged connector
- Failed PCM (rare)
02. Symptoms You Will Notice
- Check engine light illuminated
- Reduced engine performance or limp mode
- Increased diesel exhaust fluid consumption
- 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 injection valve connector and wiring for damage, corrosion, or loose connections.
Step 3: Measure resistance across the valve solenoid; compare to manufacturer specs (typically 2-10 ohms).
Step 4: Check for voltage at the valve connector with the ignition on; should be battery voltage. If low, test the circuit for shorts or opens.
Step 5: If wiring and valve are okay, test the PCM output or replace the valve.
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 the SCR system may not function properly, leading to increased emissions and potential limp mode. Short trips to a repair shop are acceptable.
How much does it cost to fix?▼
The cost typically ranges from $150 to $400, including parts (valve $50-$200) and labor (1-2 hours).