P3400 Cylinder Deactivation System Bank 1
OBD-II Trouble Code Technical Description
Cylinder Deactivation System Bank 1
What does that mean?
This generic powertrain diagnostic trouble code (DTC) typically applies to many OBD-II vehicles. That may include but is not limited to vehicles from Honda, Dodge, Ram, GMC, Chevrolet, Chrysler, Pontiac, etc.
A stored code P3400 means that the powertrain control module (PCM) has detected an abnormality in the cylinder deactivation system for engine bank one.
Bank 1 denotes the bank of the engine which contains the number one cylinder. The location of the number one cylinder varies by make and model. Consult your service manual (or alternate source of vehicle information) for the location of the number one cylinder for the vehicle in question - never make assumptions where this is concerned.
Cylinder deactivation (also known as variable displacement) systems are designed for fuel conservation purposes. They are primarily used in vehicles equipped with an engine that has more than eight-cylinders.
Under certain driving conditions, all of the engine's horsepower is not needed. These driving conditions typically involve low throttle and highway speeds. When these circumstances arise, the cylinder deactivation system is designed to disable corresponding cylinders and conserve fuel.
The variable valve timing solenoids are utilized to close the intake and exhaust valves for the cylinders that are deactivated. The purpose of this is twofold; first, it traps spent exhaust gases in the cylinder and forms a sort of air damper. This reduces vibration and makes cylinder deactivation operation smoother. Secondly, the trapped exhaust is compressed on the piston up stroke. The compressed exhaust serves to propel the piston back downward and provide an even greater degree of overall engine balance.
In addition to the valves being closed on the deactivated cylinders, the cylinder deactivation system also disables fuel flow to the affected cylinders. There is usually no noticeable loss of power or torque when the cylinder deactivation system becomes operational.
If a situation arises in which the PCM cannot make the cylinder deactivation system operational (for engine bank one), or if the PCM detects that the cylinder deactivation system has become inadvertently operational, a code P3400 will be stored and a malfunction indicator lamp (MIL) may be illuminated.
Cylinder Deactivation Engine:
What is the severity of this DTC?
Aside from the fact that cylinder deactivation problems may diminish fuel efficiency, the possible causes may lead to catastrophic engine failure. The P3400 should be rectified as soon as possible and classified as severe.
What are some of the symptoms of the code?
Symptoms of a P3400 trouble code may include:
Diminished fuel efficiency Reduced engine performance Other cylinder deactivation codes Engine misfire codesWhat are some of the common causes of the code?
Causes for this code may include:
Low engine oil level or pressure Defective valve timing control solenoid/s Open or shorted cylinder deactivation circuit/s Faulty PCM or PCM programming errorWhat are some P3400 troubleshooting steps?
Note: There are known technical service bulletins (TSBs) for certain Honda & Acura vehicles that pertain to this code. They are Honda TSB 11-033, Honda TSB 13-031, and Honda TSB 13-055.
Components which are critical to the operation of the cylinder deactivation system frequently require assistance from engine oil pressure. Because of this, diagnosing any cylinder deactivation codes should begin by making sure that the engine is filled to the proper level with the appropriate oil and that engine oil pressure is within specifications. If there is doubt about actual engine oil pressure; a manual oil pressure test is in order.<
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