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Are you having difficulties with “check engine” lights? We’ve all been there.
If the code P0301 keeps showing up and you have no idea how what that means, you’re in the right place. Today, you’ll learn everything you need to know about the P0301 code: Cylinder 1 Misfire.
This code is a general onboard diagnostic (OBD) code for vehicles. It indicates that the cylinder no. 1 in the engine is experiencing a misfire.
This means that the cylinder isn’t getting enough spark, which results in the misfiring condition.
OBD codes are generic codes that apply to all car models that are newer than 1996.
Typically, most vehicles have 4 to 6 cylinders in the engine. Each one of these cylinders first has a spark plug at the end. These spark plugs fire in order to burn fuel.
Upon burning the fuel, the engine’s crankshaft is powered by the released energy from fuel combustion. However, the cylinders are the parts responsible for controlling the speed of rotation of the crankshaft. The rotation is expressed in rounds per minute (RPM)
If one of the cylinder misfires, it affects the RPM of the crankshaft. When the Powertrain control module (PCM) detects any decrease or increase in the RPM that’s higher than 2%, it’ll store the code P0301.
If the increase of decrease in the RPM is between 2 to 10 percent, the PCM will illuminate the “check engine” lights on the dashboard.
However, if the change in the crankshaft’s RPM is more than 10%, the “check engine” light will start blinking. The higher the percentage of change in the RPM, the more drastic the problem should be.
There are many factors that cause the P0301 code. Here’s a list of the most common reasons:
In addition to the popular reasons, there are other uncommon reasons for the P0301 Code, including
Other Troubleshooting Codes about Cylinder-Misfire
In some rare events, the problem might be a faulty PCM. In that case, you’ll have to reprogram the PCM or replace it altogether.
They use a special tool (OBD-II scanner) to freeze the frame data stored in the PCM. If there were no symptoms of the problem, they reset the code and test drive the car. If the problem doesn’t return, you’re good to go.
However, if the problem comes back, this indicates a deeper problem. As a result, they continue their diagnosis as follows:
They replace the spark plugs, the wire, and the coils if needed and redo the test drive. If the code shows up they inspect other, causing agents such as:
After they find the cause for the error, they can repair it and check for any other codes.
Following that, they take the vehicle for a test drive to ensure that the problem doesn’t come back. Although it’s rare, if the P0301 shows up again, they’ll check the compression system of the cylinder.
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With that said, you now have a better understanding of the P0301 code. Unlike many other codes, this one is particularly alarming.
You should fix it as soon as you can, as driving a vehicle with misfires for a long time will cause some serious consequences to your engine. It might even lead to cylinder 1 damage. As a result, you might have to replace the whole engine.
James is a certified auto technician specializing in commercial vehicles. With 30 years of experience under his belt, James has encountered almost every type of automotive issue there is! Besides his day job at the repair shop, he is also an amateur race car driver.