Cylinder 2 Deactivation/Intake Valve Control Circuit High
The powertrain control module (PCM) has detected an unexpectedly high electrical voltage in the control circuit for the cylinder 2 deactivation or intake valve solenoid. This high voltage condition typically indicates a short to power or an open circuit, preventing the engine from properly managing its cylinder deactivation system.
While the vehicle can usually still be driven, the cylinder deactivation system will be disabled, leading to reduced fuel economy and potential rough running. It should be diagnosed soon to prevent further drivability issues or stress on engine components.
Common symptoms
- Illuminated Check Engine Light
- Decreased fuel efficiency
- Engine runs rough or misfires
- Lack of engine power during acceleration
- Noticeable engine vibration when cylinder deactivation is commanded
Likely causes
- Low engine oil level or dirty engine oil
- Faulty cylinder 2 deactivation/intake valve solenoid
- Corroded or damaged electrical connector at the solenoid
- Wiring shorted to voltage in the control circuit
- Faulty Powertrain Control Module (PCM)
What to check before replacing parts
Check the engine oil level and condition.
Look for: Low oil levels or excessively dirty/sludged oil, which can prevent hydraulic deactivation solenoids from operating correctly.
Visually inspect the wiring and connector for the cylinder 2 deactivation solenoid.
Look for: Frayed wires, melted insulation, or corroded pins that could cause a short to voltage or high resistance in the circuit.
Measure the resistance of the cylinder 2 deactivation solenoid using a multimeter.
Look for: An out-of-spec resistance reading (usually an open circuit or very high ohms) indicating an internal solenoid failure.
Test the control circuit for a short to voltage.
Look for: Voltage present on the control wire when the PCM is not commanding the solenoid on, indicating a wiring short to power.
Use a bi-directional scan tool to command the cylinder 2 deactivation solenoid on and off.
Look for: A lack of audible clicking from the solenoid or no change in circuit state on the scan tool data, confirming a circuit or component failure.
This page explains the generic P3412 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.
Gear guide: Best OBD2 ScannersRead this code yourself next time — from $20 Bluetooth dongles to bidirectional scan tools.Rather have a pro handle it? Find a vetted local mechanic.