AutoCodes – Nissan – P0303 2009 Nissan Altima Sedan

P0303 2009 Nissan Altima Sedan 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 2009 Nissan Altima Sedan 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 11,641
How popular is this code, among other codes? Low
Table of contents Created and updated by William Orellana on Aug 08, 2022
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Code P0303 2009 Nissan Altima Sedan 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 2009 Nissan Altima Sedan - Number 3 Cylinder Misfire Detected - AutoCodes.com
P0303 2009 Nissan Altima Sedan Code - Number 3 Cylinder Misfire Detected

What are the Possible Causes of the DTC P0303 2009 Nissan Altima Sedan?

  • 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 2009 Nissan Altima Sedan?

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.

Code Tech Notes

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0303 2009 Nissan Altima Sedan 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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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 2009 Nissan Altima Sedan Code

1. What are common symptoms of OBDII code P0303 (Number 3 Cylinder Misfire Detected) on a 2009 Nissan Altima Sedan?

- Common symptoms include rough idling, decreased engine performance, and potential engine vibrations.

2. What are the possible causes of a P0303 code on a 2009 Nissan Altima Sedan?

- Potential causes may include faulty spark plugs, a malfunctioning ignition coil, clogged fuel injectors, or low compression in the number 3 cylinder.

3. How can I diagnose the root cause of a P0303 code on my 2009 Nissan Altima Sedan?

- Diagnose by checking spark plugs, ignition coil, fuel injectors, compression levels, and conducting a visual inspection of related components.

4. Can driving with a P0303 code on a 2009 Nissan Altima Sedan cause further damage?

- Continuing to drive with a misfire can potentially damage the catalytic converter and other engine components over time.

5. How can I repair a P0303 code on a 2009 Nissan Altima Sedan?

- Repair options may include replacing spark plugs, ignition coil, fuel injectors, or addressing any underlying compression issues in the number 3 cylinder.

6. Are there any DIY tips for addressing a P0303 code on a 2009 Nissan Altima Sedan?

- If you have experience, you may attempt to replace spark plugs or ignition coils, but more complex issues should be addressed by a professional mechanic.

7. Will resetting the OBDII code clear up a P0303 issue on a 2009 Nissan Altima Sedan?

- Resetting the code may temporarily turn off the check engine light, but it will not fix the underlying problem causing the misfire.

8. What is the average cost to repair a P0303 code on a 2009 Nissan Altima Sedan?

- The cost can vary depending on the cause of the misfire, but expect to pay anywhere from $100 to $500 for parts and labor.

9. Can a P0303 code on a 2009 Nissan Altima Sedan lead to failing an emissions test?

- Yes, a misfire can cause increased emissions, potentially leading to failing an emissions test.

10. Is it safe to drive my 2009 Nissan Altima Sedan with a P0303 code?

- It is not recommended to continue driving with a misfire as it can lead to further damage and potential safety hazards.

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