AutoCodes - OBDII Code List - P0300

P0300 - Cylinder Misfire Detected Random Cylinders

Repair Importance Level: 3/3
Repair Difficulty Level: 3/3
What does this mean?
Table of contents

P0300 Possible Causes

What does this mean?
  • Faulty spark plug (s)
  • Faulty ignition coil (s)
  • Clogged or faulty fuel injector (s)
  • Intake air leak
  • Fuel injectors harness is open or shorted
  • Fuel Injectors circuit poor electrical connection
  • Ignition coils harness is open or shorted
  • Ignition coils circuit poor electrical connection
  • Insufficient cylinders compression
  • Incorrect fuel pressure

How do I fix code P0300?

Check the "Possible Causes" listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector's pins.
How much do you know about cars?

Take the AutoCodes.com automotive tests and turbo-charge your car repair knowledge

Play Now

Tech Notes

What does this mean?
The P0300 code means that a cylinder(s) is misfiring or is randomly misfiring. Start by checking for intake leaks, intake gaskets are a common cause of multi-cylinder misfiring. If no leaks are found the next step is to replace the spark plugs. If the problem persists more tests need to be done to diagnose the problem, see 'Possible Causes'.





User Submitted Video

Cost of diagnosing the P0300 code

Labor: 1.0

The cost of diagnosing the P0300 code is 1.0 hour of labor. The auto repair's diagnosis time and labor rates vary by location, vehicle's make and model, and even your engine type. Most auto repair shops charge between $75 and $150 per hour.

Possible Symptoms

  • Engine Light ON (or Service Engine Soon Warning Light)
  • Lack/loss of power
  • Hard start
  • Engine hesitation

P0300 Description

The Engine Control Module (ECM) uses information from the crankshaft position sensor and the camshaft position sensor to determine when an engine cylinder misfire is occurring. By monitoring variations in the crankshaft rotation speed for each cylinder, the ECM can detect individual cylinder misfire events.
Extreme cylinder misfire events can cause catalytic converter damage. The malfunction indicator lamp (MIL) will flash when the conditions for catalytic converter damage are present. The Diagnostic Trouble Codes (DTC) P0301 through P0306 (or P0301 through P0308) correspond to cylinders 1 through 6 (or 1 through 8). When the ECM detects that one or more specific cylinders are misfiring, the DTC for the respective misfiring cylinder will set, and up to 2 of the corresponding fuel injectors are disabled for a minimum of 30 s. The ECM will then re-enable the fuel injector and, after approximately 200 engine revolutions, will determine if the misfire is still present. If the misfire is still present, the ECM will disable the fuel injector again repeating the process. If the misfire is not present, the fuel injector will remain enabled by the ECM. In Spark Ignition Direct Injection (SIDI) system applications, if a fuel injector fault DTC is set during a misfire event, the ECM will not re-enable the injector.
OBDII Code P0300 - Cylinder Misfire Detected Random Cylinders - AutoCodes.com

More Information

Need more information on how to fix the P0300 code?
Get Access to Factory Service Manuals

Information for specific makes

Need more help?

Get the P0300 code diagnosed by a professional: Find a repair shop in your area

Related Information

Comments

Help us improve AutoCodes.com. Leave a comment below or tell us if the information above helps you fix the code. What are the symptoms on your vehicle for the P0300 code? Have you replaced any parts?
Any information is appreciated. Thanks
Top ⇧
Repair Importance Level: 3
 
1=Low 2=Medium 3=High What is this?
Repair Difficulty Level: 3
 
1=Easy 2=Moderate 3=Hard What is this?

All OBDII Codes

Support AutoCodes.com

Related Articles

Browse Codes by Make

Browse Codes for Specific Model-Year