What does it mean?
P3427 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Cylinder 4 Deactivation/Intake Valve Control Circuit Low . 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
- MIL (check engine lamp) on and frequently resetting after being cleared
- Cylinder deactivation locked out, so fuel consumption rises
- Rough idle with vibration that worsens as the system attempts to switch
- Ticking or knocking from the top of the engine
- Cylinder 4 misfire noticeable at low speed
- Reduced power or limp mode on some applications
Likely causes
- Chafed control wire grounding against the cylinder head, a loom clip or a bracket edge
- Solenoid winding shorted internally to its own body
- Oil or coolant sitting in the connector and bridging the control pin to ground
- Harness pinched under a cover or manifold following earlier work on the engine
- Module output driver shorted on, holding the circuit low continuously
- Badly executed splice or aftermarket wiring tapped into this circuit
How to fix it
- Check whether neighbouring cylinders have low-circuit codes too; a pattern points at shared wiring
- Unplug the cylinder 4 solenoid and see whether the code changes to an open circuit fault
- With solenoid and module both disconnected, measure resistance from the control wire to ground
- Inspect the harness where it passes metal edges, clips and brackets for rub-through
- Compare the solenoid winding resistance against a known-good unit on the same engine
- Repair, reroute or replace the damaged harness section, or renew a shorted solenoid
- Clear the code, exercise the output through the scan tool and road test to confirm the circuit is stable