Cylinder 4 Deactivation/Intake Valve Control Circuit/Open
Code P3425 indicates an open circuit in the cylinder deactivation or intake valve control circuit for cylinder 4. This system, often found in engines with Active Fuel Management (AFM) or Variable Valve Timing (VVT), uses solenoids or actuators to disable intake valves during light load to improve fuel economy. An open circuit means there is a break in the electrical path, preventing the control module from commanding the valve deactivation. This can cause a misfire, reduced fuel economy, and potential engine damage if left unaddressed.
1. Most Common Causes
- Faulty cylinder deactivation solenoid on cylinder 4
- Open or shorted wiring in the control circuit
- Corroded or loose connector at the solenoid
- Failed engine control module (ECM)
2. Symptoms You Will Notice
- Check Engine Light illuminated
- Engine misfire or rough idle
- Reduced fuel economy
- Loss of power or hesitation
3. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data.
Step 2: Visually inspect the wiring and connector for cylinder 4 deactivation solenoid for damage, corrosion, or loose pins.
Step 3: Use a multimeter to check resistance of the solenoid; compare to manufacturer specs (typically 10-30 ohms).
Step 4: Check for voltage and ground at the solenoid connector with the engine running; if missing, trace circuit back to ECM.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended. Driving with an open circuit can cause misfires, reduced fuel economy, and potential catalytic converter damage. Have it diagnosed promptly.
How much does it cost to fix?▼
Repair costs typically range from $50 to $150 for parts and labor, depending on whether it's a simple wiring repair or solenoid replacement.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.