P0300 code ( Symptoms, Causes, Fixes, & Cost) (2022)

A P0300 code is defined as a multiple or random cylinder misfire. Read below to find out What does P0300 code mean, symptoms, and how this code can be fixed. 

What does P0300 code mean?

A P0300 code means that the Powertrain Control Module or engine computer has identified there is a misfire on multiple cylinders. 

Like other power train related codes, a P0300 code is identified by the Powertrain Control Module (PCM). It detects this code by using the crankshaft position sensor and a tone wheel.

By watching the crankshaft speed variations between the individual cylinders the PCM can detect when they exceed a certain value. This value is based on other sensor inputs but generally engine load and rpm are the most common inputs used. 

A P0300 code is set when the PCM cannot identify which cylinder is causing the misfire due to multiple cylinders misfiring at one time.

 If only one cylinder was misfiring the PCM would identify which cylinder is misfiring and display a different code. P0301 for example, would identify a cylinder #1 misfire. 


-Check engine light illuminated (Flashing check engine light, pull over and call a tow truck before driving any further)

-Vibration throughout vehicle, rough idle (Vibration is caused by the engine misfiring and not running smoothly)

-Lack of acceleration, engine is running rough, depending on severity of condition vehicle may not start

-Noticeable increase in fuel consumption

Common Causes for P0300 code

There are many common causes for P0300, some are listed below:

  • Plugged catalytic converter
  • Dirty or Clogged air filter
  • Damaged fuel filter
  • Incorrect reading/Faulty oxygen sensors
  • worn out/faulty spark plugs
  • damaged or worn spark plug wires 
  • faulty or worn ignition coil
  • faulty distributor assembly
  • sensor issues ( crankshaft position sensor, MAP sensor, MAF sensor)
  • EGR failure 
  • PCM or wiring issues ( rubbed through, broken, or corroded wires)

How do I fix code P0300?

A P0300 code can be difficult to fix. There are many components that need to be ruled out before you can determine which component is faulty.

Is the air filter clean? Has the fuel filter been replaced? All these are questions that you can ask yourself before you call a technician or spend more time trying to figure out what is the cause of a P0300 code.

Check for other codes that could indicate an issue with a sensor on the vehicle. If you have a Mass Air Flow sensor code then this may be the common cause for P0300 code. 

As a technician my suggestions would be to rule out the obvious. One of the  most common causes of a P0300 code is worn out spark plugs. Spark plugs that have been in the vehicle so long the electrodes have eroded away and no longer provide proper spark.

Check to see if the spark plugs have been replaced, if they have not now would be an excellent time to do this and rule out this as a cause. 


Can I drive my vehicle with P0300

You can drive your vehicle with a P0300 code as long as the check engine light is solid and not flashing. 

If the check engine light is flashing it indicates a catalyst damaging event. This indicates that damage is occurring to your engines catalytic converter and should be shut down as soon as possible.

As we mentioned above, if the check engine light is flashing, pull over to the side of the road and call a tow truck. 

If the light is on solid, you can drive the vehicle to the nearest service station. It may be possible that the check engine light may begin to flash at any point with this code.

How much does it cost to fix?

A P0300 code can vary in cost to fix. Depending on the type of failure that the vehicle has seen the price can range anywhere from $20 to thousands of dollars. Here are a few more common items and an idea of their related costs.

  • Catalytic Converter- $500-$2500 
  • Oxygen Sensor-$100-$400
  • spark plugs-$100-$500
  • Ignition Coil- $150-$300
  • Engine Sensor-$40-$240
  • EGR failure-$150-$1500
  • PCM or wiring issues-$10-$1500

Most codes that are related to a P0300 or codes that may be set along with P0300 are engine sensor codes as well as individual cylinder misfire codes, such as P0301, P0302, etc.

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