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P0303 Nissan Code - Number 3 Cylinder Misfire Detected

Quick Answer

When a misfire occurs, engine speed will fluctuate. Common causes include Faulty Spark Plug #3, Clogged or faulty Fuel Injector #3, Faulty Ignition Coil #3. 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
P0303 Nissan indicates Number 3 Cylinder Misfire Detected.
Common causes
Common causes include Faulty Spark Plug #3, Clogged or faulty Fuel Injector #3, Faulty Ignition Coil #3.
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.
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Code Popularity 111,952
How popular is this code, among other codes? Medium
What is this?
Table of contents Created and updated by William Orellana on Aug 08, 2022
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Code P0303 Nissan Description

When a misfire occurs, engine speed will fluctuate. If the engine speed fluctuates enough to cause the Crankshaft Position (CKP) sensor signal to vary, the Engine Control Module (ECM) can determine that a misfire is occurring. The Diagnostic Trouble Code (DTC) will be set when the Engine Control Module monitors the crankshaft speed and has detected that engine cylinder #3 is misfiring.
OBDII Code P0303 Nissan - Number 3 Cylinder Misfire Detected - AutoCodes.com
P0303 Nissan Code - Number 3 Cylinder Misfire Detected
What does this mean?

What are the Possible Causes of the DTC P0303 Nissan?

  • Faulty Spark Plug #3
  • Clogged or faulty Fuel Injector #3
  • Faulty Ignition Coil #3
  • Fuel Injector #3 harness is open or shorted
  • Fuel Injector #3 circuit poor electrical connection
  • Ignition Coil #3 harness is open or shorted
  • Ignition Coil #3 circuit poor electrical connection
  • Insufficient cylinder 3 compression
  • Incorrect fuel pressure
  • Intake air leak

How to Fix the DTC P0303 Nissan?

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 P0303 code means that cylinder #3 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 #3. If the problem persists more tests need to be done to diagnose the problem. See "Possible Causes" for the most common problems.





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What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0303 Nissan 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.

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Information for Specific Nissan Models

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 P0303 Nissan Code

1. What are the common symptoms of OBDII code P0303 (Nissan)?

- Common symptoms of OBDII code P0303 include engine misfires, rough idling, loss of power, and potential engine vibrations.

2. What are the possible causes of a number 3 cylinder misfire in a Nissan vehicle?

- Possible causes of a number 3 cylinder misfire in a Nissan vehicle may include faulty spark plugs, a defective ignition coil, a clogged fuel injector, vacuum leaks, or low compression in the cylinder.

3. How can I diagnose the source of the number 3 cylinder misfire in my Nissan?

- To diagnose the source of the number 3 cylinder misfire, you can perform a compression test, inspect the spark plugs and ignition coil, check for vacuum leaks, and use a scan tool to monitor live data while the engine is running.

4. What are some tips for repairing OBDII code P0303 in a Nissan?

- Some repair tips for OBDII code P0303 in a Nissan include replacing the spark plugs, inspecting and replacing the ignition coil if necessary, cleaning or replacing the fuel injector, checking for vacuum leaks, and performing a compression test.

5. Can driving with OBDII code P0303 (Nissan) cause further damage to the vehicle?

- Continuing to drive with OBDII code P0303 in a Nissan can potentially cause damage to the catalytic converter, oxygen sensors, and other engine components over time due to the unburned fuel entering the exhaust system.

6. Is it safe to ignore OBDII code P0303 (Nissan) and continue driving the vehicle?

- It is not recommended to ignore OBDII code P0303 in a Nissan as it can lead to poor engine performance, reduced fuel efficiency, and potential damage to other engine components. It is best to address the issue promptly.

7. How much does it typically cost to repair OBDII code P0303 in a Nissan?

- The cost to repair OBDII code P0303 in a Nissan can vary depending on the underlying cause of the misfire. Costs may include parts such as spark plugs, ignition coils, or fuel injectors, as well as labor charges if professional assistance is needed.

8. Can a DIY enthusiast fix OBDII code P0303 in a Nissan at home?

- Depending on the cause of the misfire, a DIY enthusiast with the necessary tools and knowledge may be able to address OBDII code P0303 in a Nissan at home by replacing spark plugs, inspecting ignition components, and checking for vacuum leaks.

9. How important is it to address OBDII code P0303 promptly in a Nissan?

- Addressing OBDII code P0303 promptly in a Nissan is important to prevent potential engine damage, ensure optimal performance, maintain fuel efficiency, and avoid more costly repairs in the future.

10. Can extreme weather conditions or poor fuel quality trigger OBDII code P0303 in a Nissan?

- Extreme weather conditions or poor fuel quality can sometimes contribute to the occurrence of OBDII code P0303 in a Nissan by affecting the combustion process in the engine. It is important to use quality fuel and maintain the vehicle properly to reduce the risk of misfires.

Discuss the causes and fixes for P0303 Nissan OBDII Code

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  • How to fix Cylinder Misfire on 2007-2012 Nissan Altima:

    https://youtu.be/pP0I-iSBUF4

    Reply to Comment

  • So I had people tell me that it was the crankshaft sensor but after replacing it it made no difference so I went back to basic automotive trouble shooting I changed the plugs is a pain but if you do it it's free. After the plug I checked the injectors cleaned them with cleaner and a piece of wire cut with a nice point. Don't forget after removing the intake manifold to replace the gasket. You should be satisfied by this point if still problems most likely you need to replace a coil pack or single... if still no luck bank 2 crankshaft sensor is probably bad possibly even bank 2 ...bank 1 will throw a p0345. .....me I got plugs and manifold gasket and one coil and was good to go

    Other than this I have done
    Alternator
    Radiator
    Wheel bearing
    Control arms
    Tie rods and sway bars
    Strut tower
    Cv boots
    Plugs
    All before 150,000 when I did most of it at 50.000 it's crazy how much goes wrong and how this car is not cheap to fix

    Reply to Comment
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