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DTC codes / P34xx · Auxiliary emission controls / P3428

P3428Cylinder 4 Deactivation/lntake Valve Control Circuit High

P3428 is a manufacturer-specific diagnostic trouble code that indicates the powertrain control module (PCM) has detected an abnormally high voltage on the control circuit for the cylinder 4 deactivation/intake valve. This circuit typically controls an oil control solenoid or actuator that enables cylinder deactivation, and a high voltage reading means the PCM sees voltage above the expected range, often due to an open circuit, short to power, or a failed solenoid.

SystemPowertrain
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyIntermediate
AreaAuxiliary emission controls

Symptoms you may notice

  • Illumination of the check engine light, often with no other noticeable symptoms.
  • Rough or erratic engine idle, especially when the engine tries to enter cylinder deactivation mode.
  • Reduced fuel economy because the engine may stay in full-cylinder operation.
  • A slight vibration or shudder during light-throttle cruising when deactivation is commanded.
  • In some cases, the engine may enter a limp mode that limits cylinder deactivation and illuminates a message on the dash.

Common causes, most likely first

  1. Failed cylinder 4 deactivation solenoid or intake valve control actuator, causing an open or high-resistance circuit.
  2. Damaged, chafed, or disconnected wiring in the control circuit between the PCM and the solenoid.
  3. Corroded or loose electrical connector at the solenoid or at the PCM, creating high resistance.
  4. Short to voltage on the control circuit, often from a rubbed wire touching a power source.
  5. Faulty powertrain control module (PCM) driver for that circuit, though this is less common.
  6. Internal mechanical binding in the cylinder deactivation mechanism that overloads the solenoid and affects circuit feedback.

How to diagnose and fix it

  1. Connect a scan tool and verify P3428 is current, then check for any related codes and freeze-frame data to confirm the fault conditions.
  2. Inspect the wiring harness and connector at the cylinder 4 deactivation solenoid for damage, corrosion, or loose pins, and repair as needed.
  3. Measure resistance of the solenoid with a multimeter and compare to the manufacturer's specification; replace the solenoid if out of range.
  4. With the key on and engine off, backprobe the control circuit at the PCM to check for a short to voltage or an open circuit; repair the wire if faulty.
  5. If the circuit and solenoid test good, perform a bidirectional test of the solenoid with a scan tool to confirm the PCM can command it on and off.
  6. Check for mechanical issues in the cylinder deactivation system, such as a stuck lifter or oil pressure problem, that could cause the solenoid to draw abnormal current.
  7. Clear the code and perform a road test to verify the repair, ensuring the monitor for cylinder deactivation runs and passes.

What a high voltage code really means

  • A high voltage code on a solenoid control circuit often indicates an open circuit or a poor connection rather than a shorted solenoid, so inspect connectors and ground points before replacing parts.
  • Some vehicles set this code only when the engine is cold or during specific deactivation conditions, so a simple key-on test may not reveal the fault; a test drive with a scan tool recording live data is often necessary.
  • A weak or failing battery or charging system can cause erratic voltage readings that mimic a circuit fault, so always verify battery and charging system health first.
  • The cylinder 4 deactivation solenoid shares oil galleries with other cylinders, so sludge or low oil pressure can cause mechanical binding that leads to electrical codes without any wiring problem.
  • After repairs, the PCM may need to relearn the deactivation system; failing to complete a relearn or drive cycle can leave the code pending and confuse the diagnosis.

Can I keep driving with P3428?

You can generally continue driving with P3428, but avoid heavy loads and aggressive acceleration because the engine may stay in full-cylinder mode and consume more fuel. If the check engine light flashes or you notice severe misfiring, stop driving and have the vehicle inspected promptly.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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