Cylinder 3 Exhaust Valve Control Circuit/Open
Code P3421 indicates an open or malfunction in the exhaust valve control circuit for cylinder 3. This circuit is part of the variable valve timing (VVT) system, which adjusts valve timing for optimal performance and emissions. An open circuit means the engine control module (ECM) detects a break or high resistance in the wiring or solenoid, preventing proper valve actuation. This can cause rough idle, reduced power, and increased emissions.
01. Most Common Causes
- Faulty exhaust valve control solenoid on cylinder 3
- Open or shorted wiring in the control circuit
- Corroded or loose connector at the solenoid
- Failed engine control module (rare)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Rough idle or misfire on cylinder 3
- Reduced engine power and fuel economy
- Possible hesitation or stumbling during acceleration
03. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data.
Step 2: Visually inspect wiring and connector at cylinder 3 exhaust valve solenoid for damage or corrosion.
Step 3: Test solenoid resistance with a multimeter (compare to spec, typically 6-12 ohms).
Step 4: Check for voltage and ground at solenoid connector with key on engine off.
Step 5: If wiring and solenoid are good, test ECM output or swap solenoid with another cylinder to confirm.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances. The issue can cause poor performance, increased emissions, and potential damage to the catalytic converter if misfiring persists.
How much does it cost to fix?▼
Repair costs typically range from $150 to $400, depending on whether the solenoid, wiring, or connector needs replacement. Labor is usually 1-2 hours.