HomeTrouble CodesP3459

P3459 — Cylinder 8 Deactivationintake Valve Control Circuit Low

Manufacturer-specificPowertrain (engine & transmission)

Code P3459 indicates that the engine control module has detected a voltage signal below the normal threshold in the control circuit for the cylinder 8 intake valve deactivation solenoid. This prevents the system from correctly disabling cylinder 8 to improve fuel efficiency.

Symptoms

What causes it — most likely first

1. Faulty Deactivation Solenoid

An internal electrical short or failure within the cylinder 8 intake valve solenoid.

2. Wiring Harness Damage

Frayed, rubbed, or shorted wires in the circuit leading to the solenoid.

3. Corroded Connectors

Corrosion or contamination at the solenoid electrical connector causing poor contact or a voltage drop.

4. Blown Fuse

A blown fuse in the circuit providing power to the cylinder deactivation system.

5. PCM/ECM Failure

An internal failure of the control module's driver circuit for the deactivation valve.

How it's diagnosed

  1. Perform a visual inspection of the wiring harness and connectors for signs of wear or burning.
  2. Inspect the solenoid connector for corrosion or loose pins.
  3. Measure the electrical resistance of the cylinder 8 deactivation solenoid using a multimeter.
  4. Check the relevant fuses in the power distribution box for continuity.
  5. Perform a wiggle test on the wiring harness while monitoring the circuit voltage.
  6. Test the PCM output signal to the solenoid to verify the module is sending the correct voltage.

Code facts & related codes

SystemPowertrain (engine & transmission)
StandardizationManufacturer-specific (P1/B1/C1/U1)

Frequently asked

Is this a mechanical failure of the engine?

No, this is an electrical circuit code referring to the control system for the valves, not a mechanical failure of the cylinder itself.

Can I continue driving with this code?

The vehicle is generally drivable, but it will not be able to deactivate cylinder 8, leading to lower fuel efficiency and potentially higher emissions.

Should I replace the PCM if I see this code?

No. The PCM is the least likely cause of P3459; the fault is almost always found in the solenoid, the wiring, or the connectors.