Reductant Injection Valve Circuit Range/Performance Bank 2 Unit 1
The P201A code indicates that the powertrain control module (PCM) has detected a range or performance issue in the reductant injection valve circuit for Bank 2, Unit 1. 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. The PCM monitors the valve's electrical circuit and operation; when the signal is out of expected range or the valve fails to perform correctly, this code is set. Common causes include a faulty reductant injection valve, wiring issues, or a defective PCM.
01. Most Common Causes
- Faulty reductant injection valve
- Open or shorted wiring in the valve circuit
- Poor electrical connection at the valve connector
- Failed PCM (rare)
02. Symptoms You Will Notice
- Illuminated Check Engine Light
- Reduced engine performance or limp mode
- Increased NOx emissions
- Possible DEF system warning messages
03. Step-by-Step Diagnosis
Step 1: Use a scan tool to retrieve all stored codes and freeze frame data.
Step 2: Visually inspect the reductant injection valve and its wiring harness for damage, corrosion, or loose connections.
Step 3: Test the valve's resistance and compare to manufacturer specifications; replace if out of range.
Step 4: Check for voltage and ground at the valve connector with the ignition on; repair wiring if missing.
Step 5: If all tests pass, suspect a PCM issue and perform further diagnostics or reprogramming.
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 the vehicle may enter limp mode and emissions will be elevated. Immediate diagnosis is advised.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for diagnosis and repair, depending on the root cause and labor rates.