Cylinder 4 Deactivation/Intake Valve Control Circuit High
Diagnostic trouble code P3428 indicates that the powertrain control module (PCM) has detected a high voltage condition in the control circuit for the cylinder 4 deactivation/intake valve. This means the PCM is unable to properly control the cylinder deactivation solenoid for cylinder 4, preventing the engine from switching between multi-displacement and full-power modes correctly.
While not immediately dangerous, this code prevents the cylinder deactivation system from functioning properly. It should be diagnosed soon to restore fuel efficiency and prevent potential drivability issues or long-term engine wear.
Common symptoms
- Illuminated Check Engine Light
- Decreased fuel efficiency
- Engine misfires or runs rough
- Lack of engine power or hesitation during acceleration
- Inability of the engine to enter cylinder deactivation mode
Likely causes
- Faulty cylinder 4 deactivation solenoid
- Low engine oil level or low oil pressure
- Wiring harness damage (short to voltage) in the cylinder 4 deactivation circuit
- Poor electrical connection at the cylinder 4 deactivation solenoid
- Restricted oil passages leading to the deactivation solenoid
- Faulty Powertrain Control Module (PCM) (rare)
What to check before replacing parts
Check the engine oil level and condition.
Look for: Ensure the oil is at the correct level and is clean. Low or dirty oil can prevent the hydraulic cylinder deactivation solenoids from operating correctly.
Inspect the wiring and connector for the cylinder 4 deactivation solenoid.
Look for: Look for frayed wires, melted insulation, or corroded pins that could cause a short to voltage or poor connection.
Test the resistance of the cylinder 4 deactivation solenoid using a multimeter.
Look for: Compare the resistance reading to the manufacturer's specification. An out-of-spec reading (often an open circuit or very high resistance) indicates a faulty solenoid.
Check for voltage at the cylinder 4 deactivation solenoid connector with the key on, engine off.
Look for: Verify that the control circuit is receiving the correct voltage from the PCM. Constant high voltage when it should be grounded indicates a wiring short to power or a PCM issue.
Perform an oil pressure test using a mechanical gauge.
Look for: Verify that the engine is producing sufficient oil pressure according to manufacturer specifications, as the deactivation system relies on proper oil pressure to function.
This page explains the generic P3428 definition and is general reference information, not a diagnosis for your specific vehicle. Actual causes, severity, and repairs vary by make, model, engine, and mileage — always confirm with a scan tool and a qualified technician before replacing parts.
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