What does it mean?
P3409 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Cylinder 2 Deactivation/Intake Valve Control Circuit/Open . This is a standardised OBD-II code. The technical definition is the same regardless of the make or model of vehicle, although specific causes and symptoms can vary between vehicles.
Symptoms
- Malfunction indicator lamp on and cylinder deactivation disabled
- Ticking or tapping from the valvetrain around cylinder 2
- Misfire and rough running, especially when the system tries to change mode
- Loss of power and an uneven idle
- Fuel economy worse than normal on steady cruising
- Fault can be intermittent, setting after vibration or when the engine is hot
Likely causes
- Broken conductor in the solenoid control or feed wire
- Solenoid coil open internally
- Connector at the solenoid corroded, oil-soaked or not fully latched
- Terminal backed out of the connector after previous service work
- Harness chafed through where it crosses a bracket or the valley cover
- Poor ground path in the solenoid circuit
- Failed output driver in the PCM
How to fix it
- Check engine oil level, condition and viscosity — this system will not operate correctly on poor oil
- Read all codes and see whether cylinder 2 misfire codes are also stored
- Inspect the solenoid connector for oil, corrosion, latching and terminal position
- Measure the solenoid resistance and compare with specification
- Check continuity from the PCM pin to the solenoid and perform a voltage-drop test
- Wiggle-test the harness with the engine running while monitoring for the fault to return
- Repair the open circuit or replace the solenoid, then verify the deactivation system cycles normally