P3425 indicates the engine control module (PCM) has detected an open circuit in the intake-valve control solenoid or wiring for cylinder 4’s deactivation system. This prevents the cylinder from switching between active and deactivated modes, potentially affecting fuel economy and engine smoothness.
The solenoid for cylinder 4’s intake valve may have an internal open circuit or mechanical failure, preventing proper operation.
Wiring between the PCM and solenoid, or the connector at either end, may be broken, shorted, or corroded, causing an open circuit.
Loose, bent, or contaminated pins in the solenoid or PCM connectors can interrupt the control signal.
A mechanically failed or stuck lifter may prevent the solenoid from operating correctly, though this typically sets additional codes.
Insufficient or poor-quality oil can impair the hydraulic operation of the deactivation system, though this usually affects multiple cylinders.
A genuine PCM fault is uncommon for P3425 and should only be considered after all other causes are ruled out.
No. The PCM is rarely the cause of P3425. The issue is almost always due to a failed solenoid, wiring problem, or poor connection. PCM replacement should only be considered after all other causes are thoroughly ruled out.
While the vehicle may still run, driving with P3425 can reduce fuel economy and may cause slight roughness or power loss. Prolonged driving in this state may also lead to additional engine wear or emissions issues.
Cylinder deactivation improves fuel efficiency by temporarily disabling some cylinders during light-load conditions (e.g., cruising). This reduces pumping losses and fuel consumption without sacrificing performance when full power is needed.
Possibly. P3425 can affect engine efficiency and emissions output, potentially causing a failure depending on local regulations and the severity of the issue.