How to fix error code P3400 Honda Pilot? (explanation and solution)

P3400 is a generic OBD2 trouble code. This indicates that your Honda Pilot’s cylinder deactivation system is having a performance problem.

This is a very common code that can be seen on cars, vans, and trucks made by Honda.

What is the Honda P3400 Engine OBD II Error Code?

Honda with error code P3400 is “Cylinder Deactivation System Bank 1”.

Some scan tools also give the message “Valve Pause System (VPS) Stuck Off, Bank 1”.

This error can be caused by several reasons, but it is usually caused by a faulty oil pressure sensor.

Be sure to check the oil level, as a low oil level will cause problems.

What does the OBD2 code P3400 mean on a Honda Pilot?

Code P3400 means there is a problem with your vehicle’s cylinder deactivation system.

Most of the time, the P3400 violations on a Honda are low engine oil levels.

Should you be concerned about this? Not really.

Your car can run perfectly on all its cylinders; therefore, the loss of its ability to reduce the use of all cylinders will in no way affect its performance.

However, you should not ignore this problem, as the possible causes can lead to engine failure if left unattended for a long time.

Therefore, this generic Diagnostic Trouble Code (DTC) should be taken seriously.

Cylinder deactivation is a feature of modern cars that allows them to forgo full use of their cylinders in order to use only a portion of them.

This feature is included in vehicles to improve fuel economy. How does it work?

When your Honda Pilot does not need maximum power, the system reduces the use of some of the cylinders to reduce fuel consumption.

Then, when more power is needed, the car resumes full use of its cylinders.

A stored DTC P3400 means that the powertrain control module (PCM) has detected a malfunction in the cylinder deactivation system of the first bank of engines, and the first bank contains the number one cylinder.

The problem with this system is not specific, as there are many factors that keep this system in motion; thus, looking at the root causes of this DTC may help in your investigation.

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Check oil and oil pressure

Check the oil level in your Pilot. If it’s low, fill it back up. This is the most common cause of a P3400 and is the first time many people find their engine uses oil pressure.

If you have an oil pressure switch and the pressure is lower than it should be (or if the oil pressure light is on), there is not enough oil pressure to operate the cylinder deactivation system.

What does the P3400 code on the stored code mean?

The first thing to check is the oil and make sure it is at the proper level and not dirty as this can cause oil pressure issues.

A bad oil pressure switch sensor is a common Honda problem and a P3400 trouble code. While this is a common cause, it is not the only thing that can cause error code P3400.

Often the rear oil pressure sensor is replaced first, as this is a common problem on Honda vehicles such as the Odyssey and is an inexpensive part.

Bad wiring or ECM can also cause this error code with a normal sensor problem.

• Low oil level;
• Old dirty oil;
• Faulty oil pressure sensor;
• Faulty cylinder deactivation solenoid;
• Open or short in cylinder deactivation solenoid harness;
• Poor electrical contact in cylinder deactivation solenoid circuit;
• Faulty mass air flow sensor;
• Faulty Throttle Position Sensor;
• Faulty intake manifold absolute pressure sensor;
• Faulty lifts;
• Limited oil passages;
• Low engine oil level;
• No oil on the tappets.

Can a VVT code be P3400 with a misfire?

Yes! Bad wiring can also trigger a P3400 code. Therefore, inspect the wires that connect to the VVT system. Any worn, broken, or burnt wires should be replaced immediately to reset the code. Other reasons include:

• Faulty mass air flow sensor
• Limited oil pressure gauge
• Faulty Throttle Position Sensors
• Bad lifters
• The faulty electrical connection in the solenoid circuit

How to diagnose a P3400 Honda Accord with wiring problems?

After diagnosing the Honda Pilot, verify that the oil pressure codes are caused by a mechanical problem before proceeding with the repair.

The oil passages sometimes fill with debris and sludge, which reduces the oil pressure sensor and reduces the efficiency of the tappets and the valve pause system timing control solenoid. Cleaning oil passages can save you the cost of unnecessary repairs.

Use an OBD II scanner to check other stored PCM codes. This can save time and point you in the right direction for repairs.

For example, bad oil pressure sensor codes near P3400 may indicate that there is not enough oil pressure to activate the cylinder shut-off system.

Defective parts should be repaired or replaced. These include wiring, faulty sensors, faulty solenoids, etc. Seek professional assistance to supervise necessary repairs and replacements.

Faulty camshaft control solenoid.

Valve timing solenoids play a vital role in the cylinder deactivation process; therefore, if they are faulty, the process may not occur and thus result in a generic DTC. The solenoids close the intake and exhaust valves of the deactivated cylinders.

If the camshaft control solenoids fail to close the valves, the cylinders will run normally instead of shutting down.

Conclusion

Many of these systems will not work if the oil level is low. If you receive this code, check the oil level in your Pilot as soon as possible. Low oil level is the most common cause of P3400.