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P3402 — Cylinder 1 Deactivationintake Valve Control Circuit Performance

Manufacturer-specificPowertrain (engine & transmission)

This code indicates that the engine computer has detected a performance problem in the electrical circuit that controls the intake valve deactivation system for cylinder 1. This system shuts down specific cylinders to improve fuel economy during light-load driving, and the code sets when the valve fails to activate or deactivate as commanded.

Symptoms

What causes it — most likely first

1. Faulty cylinder 1 deactivation solenoid

The solenoid that controls oil pressure to the intake valve actuator can fail internally, preventing proper valve deactivation.

2. Low or incorrect engine oil level/pressure

The deactivation system relies on hydraulic pressure; low oil, wrong viscosity, or degraded oil can prevent the system from functioning correctly.

3. Wiring or connector issues

Corroded, open, or shorted wires and poor pin connections in the deactivation solenoid circuit will cause a performance fault.

4. Mechanical valvetrain failure

A collapsed deactivation lifter, stuck valve, or internal oil passage blockage can physically prevent the intake valve from responding to commands.

5. Failed PCM/ECM

The engine computer rarely fails, but an internal driver circuit malfunction can prevent it from properly operating the solenoid.

How it's diagnosed

  1. Check the engine oil level and condition; ensure the correct oil viscosity is used and top off if low.
  2. Inspect the wiring harness and electrical connector at the cylinder 1 deactivation solenoid for damage, corrosion, or loose pins.
  3. Use a bidirectional scan tool to command the cylinder 1 intake deactivation solenoid on and off, listening for a click to verify mechanical response.
  4. Test the solenoid's resistance and check for proper power and ground at the connector using a multimeter.
  5. Perform an engine oil pressure test to verify that the hydraulic system has sufficient pressure to operate the deactivation lifters.
  6. If electrical and pressure tests are normal, inspect the valvetrain for a collapsed lifter or mechanical binding.

Code facts & related codes

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

Frequently asked

Can I still drive my vehicle with a P3402 code?

It is generally safe to drive for short distances, but the engine will run rough and lack power. Extended driving with a misfire can damage the catalytic converter, so it should be repaired promptly.

Will replacing the PCM fix a P3402 code?

No, replacing the PCM is rarely the correct fix for this code. Drivers are frequently told to replace the computer, but the root cause is almost always a failed solenoid, wiring issue, or an oil pressure problem.

Can an oil change fix this code?

Yes, if the engine oil is old, heavily degraded, or the wrong viscosity, it can cause hydraulic pressure issues that trigger the code. Changing the oil and filter can sometimes resolve the problem if caught early.

What does 'cylinder deactivation' mean?

Cylinder deactivation is a fuel-saving feature that shuts down specific cylinders by keeping their intake and exhaust valves closed while driving under light loads, effectively turning a V8 into a V4 temporarily.