P3401 OBD-II Trouble Code: Cylinder 1 Deactivation Intake Valve Control Circuit Open

diagnostic check engine light

P3401 trouble code definition

Cylinder 1 Deactivation Intake Valve Control Circuit Open

What the P3401 code means

P3401 is an OBD-II generic code for the engine control module (ECM) detecting that the intake control solenoid for cylinder number 1 is either shorted, open, or has a high resistance.

What causes the P3401 code?

  • The engine control module controls the 4 or 8 cylinder modes of the engine by controlling the intake deactivating solenoids for four of the engine cylinders. The ECM can detect each of the four solenoids individually for shorts, open circuits, or high resistance.

  • The code is set when the cylinder number one has one of these three problems when the engine is commanded to go to four cylinder operation.

What are the symptoms of the P3401 code?

  • The Check Engine Light will be illuminated and the code is set in ECM memory as a fault.

  • The engine is commanded back to the eight cylinder operation and stays that way until the repairs are made. The ECM will turn off the fuel injector for the faulty cylinder.

  • The engine will misfire due to the turned off injector and solenoid failure.

How does a mechanic diagnose the P3401 code?

  • Scans for codes and documents the codes in the ECM to look at the freeze frame data for failure.

  • Checks the solenoid wiring connections for problems with loose or corroded connections

  • Checks the number one intake deactivation solenoid for the proper resistance

  • Follows the manufacturer pinpoint tests for the diagnosis and replacement of the solenoid

Common mistakes when diagnosing the P3401 code

  • Clearing ECM memory codes before checking the freeze frame data for the main failure problem, so the failure may be duplicated and repaired

  • Failing to clear the ECM codes after the codes are fixed so the ECM will enable the system to normal again

How serious is the P3401 code?

Code P3401 is a code putting the engine into failure mode and turning off the number one injector causing a misfire in that cylinder.

What repairs can fix the P3401 code?

  • Replacing the solenoid for cylinder number one
  • Repairing the connector pins for corrosion or loose connections
  • Replacing an ECM

Additional comments for consideration regarding the P3401 code

Code P3401 is for a shorted or open circuit for the 4 to 8 cylinder solenoid for the number 1 cylinder and can also be accompanied by the other 3 cylinders fault codes if the vehicle is having problems with the common power and ground they use in the harness for all the cylinders.

Follow the pinpoint test for the first code received and follow that one till it is finished and move to the next code. The same problem may be causing all the codes, but go to each one to make sure to fix the vehicle properly.

Need help with a P3401 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

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