How To Fix Honda Engine Error Code P3400

By | September 4, 2021

How To Fix Honda Engine Error Codes P3400 Sensor
A video is at the bottom of the page for a visual walk-through if needed.

What is an Engine OBDII Error Code P3400
A Honda with an Error Code P3400 is a Cylinder Deactivation System Bank 1.

This error can be caused by several things but is commonly caused by a bad oil pressure sensor,

Possible Causes Engine Error Code P3400

  • Defective cylinder deactivation solenoid
  • An open or short in the cylinder deactivation solenoid harness
  • A bad electrical connection in the cylinder deactivation solenoid circuit
  • Defective mass airflow sensor
  • Defective throttle position sensor
  • Defective intake control manifold absolute pressure sensor
  • Defective lifters
  • Restricted oil passages
  • Low engine oil level
  • Poor oil pressure on the lifters

A P3400 Error Code in a Honda is often a bad oil pressure switch sensor.

While this is a common cause, it is not the only thing that can give an Error Code P3400.

Often, the oil pressure switch sensor is replaced first since it is a common problem and low-cost part.

Example Honda Oil Pressure Switch on Amazon
Beck Arnley 201-1649 Oil Pressure Switch With Light

How To Fix Honda Engine Error Code P3400 (Replace Oil Pressure Sensor)

  1. Bad wiring or ECM could also cause this error code with the sensor the usual problem.
  2. How To Fix Honda Engine Error Codes P3400 Pic 2
    The sensor is located at the right rear of the engine behind the throttle body.

  3. It will have a wire plug harness that will need to come off to remove it.
  4. How To Fix Honda Engine Error Codes P3400

  5. A 24 mm Deep Socket will need to be used to remove it.
  6. Once the old sensor is removed, install the new unit making sure it seals good as to not leak oil.
  7. How To Fix Honda Engine Error Codes P3400 Pic 4

Fixing a P3400 is usually easy enough and falls in the backyard mechanic DIY category.

Of course, call a professional if in doubt.

The make and model of a vehicle will make a difference as some will be easier to work on than others.



2 thoughts on “How To Fix Honda Engine Error Code P3400

  1. 8thgenacccord couple exl

    My car CEL came on and 3 of the cylinders failed in bank 1 my car sounded and felt like crap. So i check it out I had a p3400 code come up and this little sensor fix it everything car is fine back to normal

  2. Manuel

    I had the code 3400 on my 2009 Odyssey. I replaced the oil sensor and checked the oil level (It is good). After 2 weeks, the light came on again. How likely I got a faulty sensor again? What else can it be? (I believe the front sensor gives a different code, should I change it as well?)


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