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)
- Bad wiring or ECM could also cause this error code with the sensor the usual problem.
- It will have a wire plug harness that will need to come off to remove it.
- A 24mm Deep Socket will need to be used to remove it.
- Once the old sensor is removed, install the new unit making sure it seals good as to not leak oil.
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.