EN

Severity: Low Code type: Generic (all makes)

P3401 Code: Cylinder 1 Deactivation/Intake Valve Control Circuit/Open

The engine computer sees a broken or open circuit to the solenoid that shuts off cylinder 1.

At a glance

Severity: 2/5 – Low2/5

Severity: Low

Meaning
Cylinder 1 Deactivation/Intake Valve Control Circuit/Open
System
Ignition & Misfire · Powertrain
Safe to drive?
Yes, short term
Typical repair cost
$10–$1,500
DIY difficulty
Moderate

On V8s with GM Active or Dynamic Fuel Management and Chrysler, Dodge, Jeep and Ram HEMI engines with MDS, each cylinder that can be switched off has its own oil-control solenoid. The engine computer switches each solenoid through its own driver and constantly checks the voltage on that circuit, whether the solenoid is commanded on or off. P3401 is purely electrical: the computer sees the condition of an open circuit on the cylinder 1 solenoid – a burnt-out coil, a broken wire or a connector that has lost contact. The system then stops deactivating cylinders, so the engine usually runs normally, just a little thirstier. Its sister codes follow the same pattern for the other switchable cylinders: P3425 for cylinder 4, P3441 for cylinder 6 and P3449 for cylinder 7; if all four appear together, look at the shared power feed first.

Can I keep driving? The car is normally fine to drive, since the engine simply runs on all eight cylinders. Get it looked at within a few weeks, and sooner if cylinder 1 starts misfiring or the engine develops a tick, which would point to a mechanical problem as well.

How to read P3401

How to read P3401P13243014
  1. P Powertrain
  2. 3 Generic (SAE)
  3. 4 Auxiliary emission controls
  4. 01 Specific fault

Symptoms

  • Check engine light with no noticeable change in how the engine runs
  • Fuel-saving mode (V4, Eco or 4-cylinder indicator) no longer engages
  • Highway fuel economy a little lower than usual
  • Occasionally a misfire on cylinder 1 if the solenoid circuit is intermittent
  • Code may come and go with engine heat or on rough roads

Possible causes

Ranked by how often each cause is behind this code (editorial estimate).

  1. Cylinder 1 solenoid coil open inside the lifter oil manifold (GM) or the MDS solenoid (HEMI) 35%
  2. Connector in the engine valley loose, corroded, oil-soaked or damaged during intake work 22%
  3. Wire chafed or broken, often near the back of the engine where the harness routes 15%
  4. Blown fuse or failed shared power feed (usually sets all four solenoid codes) 12%
  5. Poor pin fit at the engine computer connector 9%
  6. Failed driver inside the engine computer 7%

Diagnosis step by step

Diagnostic flow: P34011See which solenoid codes are stored2Check the fuse and the supplyvoltage3Measure the solenoid coil4Wiggle-test with the solenoidcommanded5Check the wire back to the computer6Replace the faulty part

  1. See which solenoid codes are stored

    Only P3401 points at the cylinder 1 solenoid or its individual wire. P3401 together with P3425, P3441 and P3449 means the common feed – a fuse, a relay or the main connector – is the likely culprit.

    Tools: OBD-II scanner

  2. Check the fuse and the supply voltage

    Find the fuse that powers the deactivation solenoids in the wiring diagram and check it. With the key on, back-probe the supply pin at the solenoid connector; you should see battery voltage, roughly 12 to 12.6 V.

    Tools: Multimeter

  3. Measure the solenoid coil

    Unplug the connector and measure resistance between the cylinder 1 control pin and the supply pin. A value in the manufacturer's range – typically in the low tens of ohms at room temperature – means the coil is fine; OL or infinite resistance confirms an open coil.

    Tools: Multimeter

  4. Wiggle-test with the solenoid commanded

    Use the scan tool's output control to switch the cylinder 1 solenoid on and off while flexing the harness and connector. If the circuit status or the code toggles as you move a particular section, the fault is in that spot.

    Tools: OBD-II scanner, Multimeter

  5. Check the wire back to the computer

    With the battery disconnected, measure continuity from the solenoid connector to the engine computer pin; it should be well under 1 ohm. Also check for short to ground and inspect the pins for spread or corroded terminals.

    Tools: Multimeter

  6. Replace the faulty part

    On GM V8s the solenoids are part of the lifter oil manifold assembly, which is replaced as a unit after removing the intake manifold. On the HEMI each MDS solenoid is a separate part in the engine valley. Clear the code and drive at steady cruise to confirm the system re-engages.

    Tools: Screwdriver, Torque wrench

Where the parts are

Ignition: coils and spark plugs per cylinder – P34011234567
Ignition: coils and spark plugs per cylinder
  1. 1Ignition coil
  2. 2Spark plug
  3. 3Fuel injector
  4. 4Camshaft sensor
  5. 5Crankshaft sensor
  6. 6Engine computer (ECM)
  7. 7Intake manifold

Repair options & costs

RepairDIY?Estimated cost
Replace blown fuse and find its cause Yes $10–$150
Repair solenoid connector or harness Yes $120–$450
Replace single MDS solenoid (HEMI) No $250–$650
Replace lifter oil manifold assembly (GM) No $500–$1,100
Replace or reprogram engine computer No $600–$1,500

Rough US estimates for parts and labor; shop rates vary by region. Not a quote.

Notes by brand

Chevrolet

On the 5.3 L and 6.2 L V8 in Silverado, Tahoe and Suburban, the deactivation solenoids sit in the lifter oil manifold under the intake manifold and aren't sold individually, so an open cylinder 1 solenoid means replacing the whole manifold assembly and its gasket.

Ram

On the 5.7 L HEMI in the Ram 1500 and Dodge models, each MDS cylinder has its own solenoid, so P3401 can often be fixed with a single solenoid and its seal once the intake manifold is off.

Emissions / smog test impact

Will fail

The check engine light is on, so the vehicle fails the OBD part of a smog or emissions test. After the repair, drive until the readiness monitors are complete.

Frequently asked questions

How is P3401 different from P3400?

P3400 means the deactivation system as a whole isn't working as intended, often for oil-pressure or lifter reasons. P3401 is narrower: the electrical circuit to the cylinder 1 solenoid is open. It's usually tracked down with a multimeter rather than an oil pressure gauge.

Can I just unplug the system and drive?

The engine already disables deactivation when it sees this code, so it runs on all cylinders. The check engine light stays on, though, which means an emissions test failure and a hidden fault if something else goes wrong.

Why do I need to remove the intake manifold?

On these V8s the solenoids sit in the valley between the cylinder banks, directly under the intake manifold. The manifold has to come off to reach them, which is where most of the labor cost comes from.

Sources