HomeTrouble CodesP0314

P0314 — Single Cylinder Misfire Cylinder Not Specified

Generic OBD-II · all makesPowertrain (engine & transmission)

Code P0314 indicates the engine control module has detected a misfire in a single cylinder but cannot identify which specific cylinder is affected. This typically occurs when the crankshaft position sensor signal is insufficient to isolate the event to one cylinder despite detecting a rotation anomaly. Continued driving with this code can damage the catalytic converter due to unburned fuel entering the exhaust.

Symptoms

What causes it — most likely first

1. Worn spark plugs or ignition coils

Degraded ignition components are the most common cause of engine misfires regardless of cylinder identification.

2. Faulty crankshaft position sensor

A weak or erratic signal from this sensor prevents the computer from determining exactly which cylinder is misfiring.

3. Damaged wiring harness near sensors

Chafed wires or poor connections at the crankshaft or camshaft sensors introduce noise that obscures cylinder data.

4. Fuel injector obstruction or failure

Insufficient fuel delivery to one or more cylinders can cause a misfire condition.

5. Intake manifold vacuum leak

Unmetered air entering the engine creates a lean condition leading to combustion instability.

6. Failed powertrain control module

Internal computer failure is extremely rare and should only be considered after all external circuits and components are verified.

How it's diagnosed

  1. Retrieve all stored codes and freeze frame data to check for accompanying sensor faults.
  2. Inspect and test spark plugs, ignition coils, and related wiring for wear or damage.
  3. Monitor crankshaft and camshaft position sensor waveforms with an oscilloscope for signal integrity.
  4. Test fuel pressure and inspect injectors for proper flow and electrical pulse.
  5. Perform a smoke test on the intake system to locate potential vacuum leaks.

Code facts & related codes

SystemPowertrain (engine & transmission)
StandardizationSAE generic — identical on every make

Frequently asked

Is it safe to drive with code P0314?

No, prolonged driving can cause overheating and permanent damage to the catalytic converter due to unburned fuel.

Why does this code not specify the cylinder number?

The engine computer detected a misfire but lacked the precise crankshaft position data required to isolate the specific cylinder.

Do I need to replace the engine computer for this code?

No, replacing the powertrain control module is rarely the correct fix and should only be considered after all sensors and wiring are proven functional.

Will clearing the code fix the problem?

No, clearing the code only resets the warning light and the underlying mechanical or electrical fault will likely cause it to return.