P0314 OBD-II Trouble Code: Single Cylinder Misfire (Cylinder not Specified)

P0314 code definition

A P0314 trouble code indicates that the Powertrain Control Module (PCM) has detected an engine misfire in a single cylinder that was powerful enough to damage the catalytic converter. In conjunction with the storage of the trouble code, the Check Engine light usually comes on. In cases where the misfire was not serious enough to cause damage to the catalytic converter, the Check Engine light might flash momentarily, while accelerating, before going off.

The PCM might also store related trouble codes dealing with individual cylinders, including a P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307, P0308, P0309, P0310, P0311, P0312, and P0313 trouble code.

What the P0314 code means

A P0314 trouble code means the engine has suffered a misfire in a non-specified cylinder. The PCM uses the position of the crankshaft, along with the camshaft position and the RPMs of the engine to detect a misfire.

What causes the P0314 code?

A P0314 trouble code can have many causes, including:

• Insufficient fuel pressure leading to a lean condition
• Excessive vacuum leaks within the engine
• A malfunction in the EGR system
• A clogged catalytic converter
• A failure in the ignition system

What are the symptoms of the P0314 code?

Common symptoms of a P0314 trouble code include a reduction in power, rough idling, and irregular acceleration, in addition to the stored trouble code and the Check Engine light illuminating.

How does a mechanic diagnose the P0314 code?

To diagnose a P0314 trouble code, a mechanic needs an advanced scanner or code reader, factory service manual, and a digital volt/ohmmeter. In addition to these tools, the mechanic should perform the following steps:

• Visually inspect all wiring, connectors, and components.

• After making all of the necessary repairs to the wiring, connectors, and components, retest the system to ensure that the problem has been fixed.

• Clear the P0314 trouble code and test drive the vehicle.

• If a code has been stored, but no symptoms are present, reset the PCM to see if the code returns.

• If the engine continues to hesitate upon acceleration, check that the vehicle is up to date on all maintenance, including tune-ups.

• If the ignition system has no problems and the engine continues to hesitate upon acceleration, inspect data from the oxygen sensor.

• Inspect the vacuum hoses to look for a possible leak there.

• Check the EGR valve to make sure it is still working properly.

• Inspect the catalytic converter to see if it is clogged.

Common mistakes when diagnosing the P0314 code

One common mistake that mechanics make when dealing with a P0314 trouble code is replacing ignition system components, thinking the problem is there without inspecting the system. While possible, most ignition misfires fall within the P0301 to P0312 trouble code range.

How serious is the P0314 code?

The storing of a P0314 trouble code means that the engine misfire is severe enough to damage the catalytic converter, and if left unfixed, could lead to an increase in vehicle emissions. In addition, engine misfires that lead to a stored P0314 trouble code impact vehicle performance, including during acceleration and idling.

What repairs can fix the P0314 code?

To repair and clear a P0314 trouble code, the mechanic should perform the following:

• Upon visually inspecting the wiring, connectors, and components, replace any worn or damaged parts

• Perform a tune-up of the vehicle engine if necessary, including replacing the spark plugs, spark plug wires, and ignition coil or packs. If the vehicle is equipped with a distributor cap, replace that and the rotor

• Check and replace the fuel filter if blocked

• Repair or replace any damage vacuum tubes in the case of a vacuum leak

• Replace the EGR valve if found to be faulty

• Replace the catalytic converter if it is clogged

Need help with a P0314 code?

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