P0301 Code: What It Is and How to Fix It (2023)

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What does the term "engine misfire" mean? Engine not firing correctly indicates that one or more of the engine's cylinders are not firing. Several engine codes warn us of misfiring in the engine cylinders. What engine code is displayed if the first cylinder of the engine keeps misfiring? It is usually the code P0301!


Intermittent misfire occurs when the cylinder only misfires under certain circumstances and not always. By comparison, the codeP0300indicates random misfires on multiple cylinders and codesP0302,P0303, yP0304they show misfires on cylinders 2, 3 and 4. The PCM identifies "misfires" by monitoring engine speed.

So what is the P0301 code? What Causes It How serious is the error code? How to fix this and how much do you have to spend on it? Here you have all the information you need!


(Video) Misfiring Engines With P0301 Code

What does the P0301 code mean?

You will get a P0301 code if the first cylinder in your engine misfires. Combustion reactions provide the energy for an engine's powertrain. When combustion in the cylinders fails, misfiring occurs, which is indicated by a sudden drop in RPM when the engine is unable to produce enough power.

The powertrain control module (PCM) stores the P0301 engine code when it detects an increase or decrease in crankshaft revolutions per minute greater than 2 percent. The Check Engine Light comes on when the percentage increase or decrease in crankshaft revolutions per minute is between 2 and 10 percent. The Check Engine Light flashes when the percentage increase or decrease in crankshaft revolutions per minute is greater than 10 percent.

An increase or decrease in RPM of more than 10% indicates that the misfire problem is serious.

What causes a P0301 code?

Various reasons can lead to cylinder misfiring. This could be due to internal engine damage or a fuel or ignition system malfunction. However, the ideal reason for the P0301 code to appear may be a worn or faulty spark plug coil pack. It usually happens when you haven't had a car service for a while. Here are some factors that can lead to the P0301 engine trouble code.

(Video) P0301 Explained - Cylinder 1 Misfire (Simple Fix)

  • Defective or worn spark plug(s).
  • Ignition problems such as faulty ignition coils
  • damaged injector
  • fuel pressure is low
  • vacuum leak
  • Defective camshaft and/or crankshaft sensors
  • dealer failure
  • Engine control shuts down
  • The presence of poor quality fuel that is dirty or old
  • Head gasket leak
  • Engine compression becomes low.
  • A lean air or fuel mixture will cause a faulty airflow sensor
  • Valve misalignment and misalignment
  • Worn valve train components
  • clogged exhaust
  • Purge valve (solenoid valve) and/or EGR valve stuck open

Symptoms of the P0301 code

The most common symptom is the Check Engine Light coming on. These are some of the symptoms of your car when it receives the engine code P0301.

  • The Check Engine Light comes on or starts flashing
  • The car is difficult or impossible to start when accelerating
  • The car engine is rough and runs rough at idle.
  • The car loses power during operation, stalls or dies at a stop
  • Increase in fuel consumption
  • Detect the smell of fuel from the exhaust.
  • The car has a jerky movement when idling or moving.

How serious is the P0301 engine code?

You should never ignore the P0301 engine code. Cylinder misfiring can cause serious engine damage if you ignore it. Severe cylinder misfiring can damage the catalytic converter, causing the Malfunction Indicator Light (MIL) to flash. Since the component is vital to the proper functioning of a car engine andReplacing the catalytic converterIt's expensive, you should take the car to a trained mechanic as soon as the code shows up.

Is it safe to drive with a P0301 code?

You should not drive with a P0301 code set, as a misfire can cause additional damage to your car. You should fix the problem immediately and take the car to a mechanic. If the Check Engine Light is flashing, the car has a serious cylinder misfire. So better not continue.

How to Diagnose the P0301 Code

Take your car to an experienced mechanic if your car shows any of the symptoms of the P0301 code. It is important to diagnose the problem before fixing it.

Steps followed by the mechanic to diagnose the code

  • Using an OBD-II scanner will collect all PCM trouble codes and freeze frame data
  • Test drive the car to see if the P0301 code returns
  • Inspect cylinder 1 spark plug wire for damage or wear
  • Inspect the spark plug barrel for damage.
  • Inspects coil packs and coil pack wires for damage or wear
  • Replace spark plugs, coil packs, and coil pack wiring as necessary. Inspect the fuel injectors and fuel injectors for damage if the code returns after replacing these components
  • Check for rust or cracks on the distributor cap and/or rotor knob
  • Diagnoses and repairs codes relevant to the P0301 code stored by the PCM.
  • Take a test drive again to see if the code persists
  • If the fault code reappears, check the compression system of cylinder 1
  • The powertrain control module may be at fault if the P0301 code persists. Then replace or reprogram the PCM

Common errors that can occur during diagnosis

Inspect the fuel injector wiring for damage before replacing the spark plugs, spark plug wires, coil packs, and coil pack wires. Although bad injectors are rare, a quick visual inspection could save time. Determine that a defective cylinder is not the cause of the problem. It is also important to diagnose and repair other associated trouble codes stored by the powertrain control module. Any of these components can cause the misfire.

How to fix the P0301 code

Fixing the misfire will depend on the cause, so it is important to diagnose the problem thoroughly. You don't want to spend a lot of money to buy new parts for your car. Even if you want to carry out the repair yourself, we recommend that you have your dealer or a trusted workshop carry out the diagnosis.

(Video) 2006 Nissan Frontier P0301 Cylinder 1 Misfire Diagnosis & FIX

Check all wires and connectors connected to cylinders, such as spark plugs B. to repair any stalling or engine hesitation. Replace ignition components if they have been in the car for a long time. Also replace the spark plugs and their wires, as well as the distributor cap and rotor if necessary. If the exhaust smells bad, check the catalytic converter and replace it if necessary. Faulty fuel injectors can also cause the code to appear.

After fixing the misfire, the code will clear after a few miles of driving.

What repairs can fix the P0301 code?

Make the following replacements or repairs on these components to resolve the P0301 engine code.

  • Defective spark plugs, spark plug wires or coils
  • Clogged EGR valves and/or pipes
  • burnt valves
  • vacuum leaks
  • Leaking head gaskets
  • Defective camshaft sensor
  • Faulty crankshaft sensor
  • Damaged mass air flow sensor, oxygen sensor, and throttle position sensor
  • Defect catalyst
  • faulty injectors

Also try these to fix engine code problems.

  • In addition to the wires, coils, and connectors, reattach the distributor cap and rotor knob.
  • Diagnose and repair other related engine codes as needed
  • Make necessary repairs to internal engine components.
  • Replace the motor if the cylinder is damaged
  • If necessary, reprogram or replace the PCM

How much does it cost to repair the P0301 code?

Several factors can lead to the P0301 code, such as worn spark plugs, low engine compression, and vacuum leaks. Therefore, it is difficult to give an exact cost without first actually evaluating the problem.

Most shops start with an hour of "diagnostic time" when you bring your car in for a diagnosis. It can cost between $75 and $150 depending on the labor price of the store. If the repair shop does the repairs for you, these diagnostic costs will be applied to other necessary repairs.

P0301 may require one or more of the following repairs to resolve the root issue if detected correctly. These prices include components and labor based on national averages. Repair costs vary by location and type of vehicle.

(Video) How To Fix A Misfire Code with Basic Hand Tools | P0300 P0301 P0302 P0303 P0304

Estimated costs

ArticleEstimated costs
ignition coils$230-$640
vacuum leak$100-$200
petrol pump$1300-$1700
fuel pressure regulator$200-$400

How do I fix the P0301 code?

It is impossible to fix this problem yourself unless you have a mechanical background. However, you can examine your engine to find out the source of the problem. When inspecting your engine's cylinder, look for the following signs of damage.

  • Presence of corroded electrical connections
  • Cracked, bent, or misplaced components
  • Liquids leak out of the cylinder.

You may be able to fix the misfire problem by replacing the spark plugs in the cylinder. See a mechanic if the problem persists after installing the new plugs.

Will it just clear a P0301 code?

Once you have made the necessary repair to the problem and it is no longer detected, the misfire code will clear after a few trips.

Find the right insurance for your car

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The final result

  • Cylinder 1 will not fire when displaying engine code P0301.
  • You must stop driving immediately when the code is displayed.
  • To avoid misfiring, catalytic converter damage, and unsafe situations, correct this code as soon as possible (preferably the same day).
  • Various factors can cause misfiring, including bad spark plugs and insufficient engine compression. Since there are so many factors that can cause a misfire, the best way to save money is to take your car to a mechanic and have the problem fixed.

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(Video) How to Fix P0301 Engine Code in 3 Minutes [2 DIY Methods / Only $4.22]


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