Secondary Air Injection Switching Valve B Circuit Malfunction
The P0415 code indicates a malfunction in the electrical circuit of the secondary air injection system switching valve B. This valve controls airflow from the air pump to the exhaust manifold to reduce emissions during cold starts. The Powertrain Control Module (PCM) detects an open, short, or excessive resistance in the valve's solenoid circuit, preventing proper operation.
01. Most Common Causes
- Faulty secondary air injection switching valve B
- Open or shorted wiring in the valve circuit
- Corroded or loose electrical connector
- Blown fuse or relay for the secondary air system
- Failed PCM (rare)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Failed emissions test
- Rough idle or hesitation on cold start
- Possible reduced fuel economy
03. Step-by-Step Diagnosis
Step 1: Use a scan tool to confirm P0415 and check for related codes.
Step 2: Visually inspect the valve B connector and wiring for damage or corrosion.
Step 3: Test the valve solenoid resistance with a multimeter (specs: 20-40 ohms).
Step 4: Check for 12V power and ground at the valve connector with the engine running.
Step 5: If wiring and valve are good, test the PCM output signal.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
Yes, but the vehicle may fail emissions testing and cold-start performance may be affected. It's best to repair promptly.
How much does it cost to fix?▼
Typically $50-$150 for parts and labor, depending on the cause. A valve replacement costs around $30-$80, plus diagnostic time.