AutoCodes.com
Login with Google
AutoCodes – Generic – P0301

P0301 Code - Cylinder 1 Misfire Detected

Quick Answer

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. Common causes include Faulty Spark Plug #1, Clogged or faulty Fuel Injector #1, Faulty Ignition Coil #1. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means
P0301 indicates Cylinder 1 Misfire Detected.
Common causes
Common causes include Faulty Spark Plug #1, Clogged or faulty Fuel Injector #1, Faulty Ignition Coil #1.
Severity
High - diagnose this code as soon as possible.
Can I drive?
Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Save to My Repairs Step-by-Step Diagnostic Guide My Repairs
AI answers can be wrong. Verify repairs with testing. Open full chat
Code Popularity 151,694
How popular is this code, among other codes? High
What is this?
Table of contents Created and updated by William Orellana on Jul 17, 2023
💬 Need more help? Ask Coddy for instant answers — it's free!

Code P0301 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 correspond to cylinders 1. 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 P0301 - Cylinder 1 Misfire Detected - AutoCodes.com
P0301 Code - Cylinder 1 Misfire Detected
What does this mean?

What are the Possible Causes of the DTC P0301?

  • Faulty Spark Plug #1
  • Clogged or faulty Fuel Injector #1
  • Faulty Ignition Coil #1
  • Fuel Injector #1 harness is open or shorted
  • Fuel Injector #1 circuit poor electrical connection
  • Ignition Coil #1 harness is open or shorted
  • Ignition Coil #1 circuit poor electrical connection
  • Insufficient cylinder 1 compression
  • Incorrect fuel pressure
  • Intake air leak

How to Fix the DTC P0301?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code Tech Notes

The P0301 code means that cylinder 1 is misfiring or is randomly misfiring. Start by checking for intake leaks and if no leaks are found the next step is to replace the spark plugs on cylinder 1. If the problem persists more tests need to be done to diagnose the problem, see "Possible Causes".













User Submitted Video

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0301 code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the P0301 code?

Need more information on how to fix the P0301 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P0301 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P0301 Code

1. What are the common symptoms of OBDII code P0301 (Cylinder 1 Misfire Detected)?

Symptoms may include engine misfiring, rough idling, loss of power, increased fuel consumption, and potentially a noticeable decrease in acceleration.

2. What are the possible causes of OBDII code P0301 (Cylinder 1 Misfire Detected)?

Common causes include faulty spark plugs, ignition coils, fuel injectors, vacuum leaks, low compression in the cylinder, or issues with the engine control module.

3. How can I diagnose the cause of OBDII code P0301?

Diagnosing the issue may involve conducting a visual inspection of spark plugs and ignition components, performing a compression test, checking for vacuum leaks, and using a scan tool to monitor live data from the engine.

4. Can driving with OBDII code P0301 (Cylinder 1 Misfire Detected) damage my engine?

Continuing to drive with a misfire can potentially cause damage to the catalytic converter, oxygen sensors, or other engine components over time. It is advisable to address the issue promptly.

5. How can I repair OBDII code P0301 (Cylinder 1 Misfire Detected)?

Repair steps may include replacing spark plugs, ignition coils, or fuel injectors, repairing vacuum leaks, addressing low compression issues, or updating the engine control module software.

6. Is it safe to continue driving with OBDII code P0301 if the symptoms are intermittent?

While intermittent symptoms may not pose an immediate danger, it is still recommended to address the underlying issue as soon as possible to prevent potential long-term damage to the engine.

7. Can bad gasoline cause OBDII code P0301 (Cylinder 1 Misfire Detected)?

Low-quality or contaminated gasoline can contribute to misfires, so it's important to use fuel from reputable sources and consider adding a fuel system cleaner if needed.

8. Will resetting the OBDII code P0301 clear the issue?

Resetting the code may temporarily turn off the check engine light, but it will not fix the underlying problem causing the misfire. It's best to diagnose and repair the issue to prevent it from recurring.

9. How long does it typically take to repair OBDII code P0301 (Cylinder 1 Misfire Detected)?

The repair time can vary depending on the exact cause of the misfire. Simple fixes like replacing spark plugs may take less than an hour, while more complex issues could require several hours or more.

10. Can extreme weather conditions trigger OBDII code P0301 (Cylinder 1 Misfire Detected)?

Extreme cold or hot weather can sometimes exacerbate existing issues with spark plugs, ignition components, or fuel delivery, potentially leading to a misfire and triggering the P0301 code.

Discuss the causes and fixes for P0301 OBDII Code

Submit a New Comment

  • Had same problem with month old reman heads, it was a broken intake valve spring.

    Reply to Comment

  • i have this problem tre times, have reset and change sparkplug one time, but get it back the same trouble, after last of time reset have its been better, i think the trouble its the coil

    Reply to Comment

  • What model and year is your vehicle? ignition coils are very common problem.

    Reply to Comment

  • Models of CA 33 ( 00-03)

    Reply to Comment

  • Could you be a bit more specific? make and model?

    Reply to Comment

  • this its a model of 00 -03 Maxima

    Reply to Comment

  • The ignition coils are very,very common problem on the Maxima. We replace ignition coils almost every week on Nissan vehicles. If there is an excessive fuel smell from the tail pipe, then it means that the problem is the fuel injector. Since you have P0301 code, then the problem is either ignition coil #1 or fuel injector #1

    Reply to Comment

  • My 08 Altima coupe was washed just like his but I didn't cover anything up. Had the shuttering and misfire cylinder 1 code and have replaced w high quality spark plugs. Ran badass for a an hour just went back out and it's there again. No engine light yet. I'm thinking th 1 ignition coil but idk.. any ideas? No prev problems 134k 4cyl

    Reply to Comment

  • Yes, sounds like a bad ignition coil.

    Reply to Comment

  • I have a 2005 Malibu maxx….Codes po301 and po455 came up yesterday. 4 months ago I just had a tuneup with new plugs, boots and wires. 2 months ago I had these codes for plug number 6. last month one of the hoses got caught in something and completely came off. now this. its neverending. I replaced the transmission already along with a lot of other things. should I keep putting money into this, tranny has less than 70,000 and I doubt its going to pass inspection come oct. its getting very rusty

    Reply to Comment

  • The P0301 code is related to the spark plugs repair. I recommend taking you vehicle back to the shop that replaced the spark plugs and wires.

    The P0455 code may not be related to the P0301. It could be just a loose or missing gas cap.

    P0455 CHEVROLET - Evaporative Emission Control System Leak Detected Gross Leak
    Read more: https://www.autocodes.com/p...

    Reply to Comment
AutoCodes App

Fix Your Car Smarter

Try the New AutoCodes App!

Get complete OBDII diagnostics, repair solutions, and cost estimates, plus AI chat support on demand.

AutoCodes App on Google Play