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For most people, if there is something wrong with their car, they feel that their only option is to take it to the mechanic. Modern vehicles come with an error code system, which gives you valuable information about what is wrong with your vehicle. This can help you diagnose it so you do not need to rely on a mechanic to fix it for you. If you receive an OBD-II scanner error code P0306 problem, it means that one of the cylinders is not firing. If you are like most people, you may not fully understand what that means. Our guide will explain what a misfiring cylinder means for your vehicle and what you can do to fix it.

Knowing What the Error Means

First, you must understand what does the code P0306 mean? Inside the engine is a series of cylinders. When the engine is running, it injects a mixture of fuel and air into the cylinders. Then, a spark is generated which combusts the fuel mixture. This explosion pushes the cylinder down, which is what generates power. The vehicle translates the pushing of the cylinders into the wheels spinning. If a cylinder is not firing, it means something has gone wrong, but there are so many different parts that work together to make the cylinders fire. Something could be wrong with any one part of this system. It could be:

  • Fuel is not being injected
  • The fuel mixture ratio is off
  • A spark is not being generated
  • The valve is not opening or closing properly
  • A vacuum leak

Luckily, the P0306 error code specifically tells you that the number six cylinder is not firing specifically. This will help you identify what might be causing this cylinder not to fire.

The Symptoms

If one of your cylinders is not firing, it is likely that you will be able to tell. The engine will likely run very choppy. You may also notice a strange scent in the emissions and diminished fuel economy. The check engine light will almost certainly be on, but it may be flashing to indicate a very serious problem has occurred. You should never ignore a misfiring cylinder. It may cause serious damage to your engine or the catalytic converter. Additionally, if the cylinder does not fire for too long, it may have trouble firing again when you do finally fix the issue. And, of course, whatever problem is causing the cylinder not to fire may cause other problems.

What You Can Do About It

So how do I fix trouble code P0306? In nearly all cases, the cylinder is not firing because a spark is not being produced. This is the easiest part of the system to break, which means it is almost always the problem. Depending on exactly what part of the spark system is malfunctioning, the issue may be simple to fix. Check if you need to change your spark plugs, and also check the spark plug wires and ignition coil for damage.

If you are not experiencing any of the above symptoms, it may be an issue with the sensor instead. The cylinder may be firing correctly, but the car thinks it is not because the sensor is broken. Using a diagram, you can find the senor and inspect it and the connectors for damage. Replacing the sensor is relatively easy.

If you still have not identified the issue, you must examine the cylinder, valves, manifold, vacuum lines, and fuel injector for mechanical issues. Keep an eye out for debris or clogs that may be impairing function, or cracks, dents, or other types of damage. You may be able to repair a damaged component, but you will likely have to replace it instead.

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