What is P3400 fault code all about? What causes the P3400 error code? How do you fix the P3400 error code? What does the Cylinder Deactivation System Bank 1 Fault mean?
Many drivers find it difficult to diagnose the problem with their vehicle. Most modern vehicles have a code system that makes this process much easier. This system communicates directly with the vehicle, and generates fault codes that indicate what’s wrong. To find the code that is causing the issue, a special scanning tool must be used. It is important to determine what the code represents and what caused it.
P3400, for example, indicates that a warning is displayed about the ‘Cylinder Deactivation System Bank 1“. This may mean little to you, as it does for many other drivers. We will tell you what to do and where it might come from.
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What is Error Code P3400?
The statement ‘The system of cylinder deactivation is defective’ is confusing. The cylinders of an engine are known to generate power. When all cylinders work, the engine is at maximum power. Some vehicles are made with more than four cylinders. A ‘cylinder deactivation’ system is a good idea if a vehicle has many cylinders. All cylinders being on all the time is not always a good thing. Only four cylinders will suffice when your vehicle is at cruising speed and the throttle is set to low. The engine switches from V8 to V4 mode when driving conditions are low. By preventing several cylinders to fire, the cylinder-deactivation system can save fuel and money.
- Close valves
- Disable fuel flow
The cylinder deactivation closes the intake valves and exhausts of the unnecessary cylinders. The valves need to be properly closed because very small explosions can occur within the cylinders. Valve components are powerful and delicate. It is easier to understand how to disable the fuel flow. Disabling cylinders has only one purpose: to save fuel. The fuel supply must be stopped to the cylinders for this to happen.
Powertrain Control Module (PCM) determines the driving conditions of the vehicle using information from mass airflow (MAF), manifold absolute pressur (MAP) and throttle position sensors.
The PCM will instruct the solenoids that deactivate the cylinders to begin the process. The solenoids that control cylinder deactivation disable cylinders 1,4,6, and 7, by restricting the oil flow to lifters and preventing intake and exhaust valves opening. The vehicle will not enter V4 mode if the MAF sensor, MAP sensor, or TP sensor do not meet the required conditions.
The PCM will generate the fault code P3400 if it detects that these sensors do not fall within the range of values for the V4 mode. This code can be seen on Honda, Dodge Ram, GMC Chevrolet Chrysler Pontiac and other brands.
What are the symptoms of P3400 fault code?
This error code is only associated with a few symptoms. The engine fault light will come on if the cylinder deactivation fails to operate or is activated unexpectedly.
- Engine fault light illuminates
- Fuel efficiency is reduced
- Engine power loss
- Engine vibration
What causes the P3400 fault code?
- Defective cylinder deactivation sonoid – Short circuit or open circuit in the wiring harness for cylinder deactivation.
- A faulty electrical connection within the solenoid circuit for deactivating the cylinder
- Faulty mass flow sensor
- Faulty throttle sensor
- Intake manifold absolute sensor faulty
- Lifters that are not working properly
- Blockage/restriction of oil lines
- Low Engine Oil Level
- Low oil pressure in lifters
How to Fix Error Code P3400?
Low oil pressure or level is the most common cause. Check your oil level, and top off your vehicle as necessary. You should perform a manual pressure test if this does not solve the problem. Then, you can drive the vehicle to see if the code appears again. If the problem persists then the fault most likely is due to a defective or damaged part. Test cylinder deactivation solenoid #1. A solenoid that is working properly will make a clicking noise and vibrate. If the cylinder deactivation solenoid #1 does not work properly, you should check the oil passages for any debris, clean them if needed, and then replace the solenoid. If the cylinder deactivation sonoid #1 functions properly, cylinder solenoid number 7 should also be checked.
Check the oil channels that lead to the lifters if the problem is not there. Clean any restricted oil passageways. Lifters should be replaced if there are no restrictions in the oil passages.
- Check engine oil pressure and level
- Replace cylinder deactivation solenoid #1
- Replace cylinder deactivation solenoid #7
- Remove dirt and debris from the oil passages for the solenoids that deactivate cylinders
- Remove dirt and debris from the oil passages in lifters
- Replace the lifters
- If due to damage the engine sump was exposed to dirt or mud, it should be disassembled completely and thoroughly cleaned.
How Important is the P3400 Fault Code?
The cylinder deactivation systems malfunctioning not only results in a decrease in fuel efficiency, but also an increase of engine emissions. System failures can lead to serious engine issues. The entire engine could fail if the fault is ignored and not repaired.
