How To Fix Honda Engine Error Code P3400

By | April 15, 2022

How To Fix Honda Engine Error Codes P3400 Sensor

What is a Honda P3400 Engine OBDII Error Code?

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 of a Honda P3400 Engine Error Code

  • 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
  • No oil 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 cause 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 Switch on Amazon
Beck Arnley 201-1649 Oil Switch With Light

How To Fix Honda Engine Error Code P3400 (Replace Oil 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 24mm 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

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

Of course, if in doubt call a professional certified mechanic.

The P3400 code will be given by an OBDII scanner tool after the Honda check engine light comes on.

Other OBDII trouble codes may also be given and also need to be looked up for the cause.

A faulty sensor is the usually cause and is commonly replaced.

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

Have you had an issue with a Honda P3400 code? Let us know your thoughts below.

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

  1. Jason

    I had the P3400 on my 2010 Honda Pilot, and looked up what could be the problem. It was like WebMD, the list of possible problems was scary. lol I followed these steps, and the hardest part was finding the new switch after I dropped it into the engine bay. The light didn’t immediately go out, so I came back in the house to see if there was some sort of delay or if I had to reset it. Then I thought maybe I changed the wrong one, ran back out to move the car back to the garage, but when I started it up, the light was out! BOOYAH! Thanks!

    Reply
  2. 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

    Reply
  3. 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?)

    Reply

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