AutoCodes – Nissan – P0303 2012 Nissan Altima Sedan

P0303 2012 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 2012 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 7,957

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Aug 08, 2022

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0303 2012 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 2012 Nissan Altima Sedan - Number 3 Cylinder Misfire Detected - AutoCodes.com — P0303 2012 Nissan Altima Sedan Code - Number 3 Cylinder Misfire Detected

What does this mean?

What are the Possible Causes of the DTC P0303 2012 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 2012 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.

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.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0303 2012 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 2012 Nissan Altima Sedan Code

1. What are the common symptoms of OBDII code P0303 in a 2012 Nissan Altima Sedan?

- Common symptoms 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 2012 Nissan Altima Sedan?

- The misfire can be caused by issues such as faulty spark plugs, a failing ignition coil, vacuum leaks, fuel delivery problems, or a malfunctioning fuel injector.

3. How can I diagnose the cause of a P0303 code in my 2012 Nissan Altima Sedan?

- You can diagnose the issue by performing a thorough inspection of the spark plugs, ignition coil, fuel injectors, and checking for vacuum leaks using a scan tool to monitor live engine data.

4. What are some repair tips for addressing a number 3 cylinder misfire in a 2012 Nissan Altima Sedan?

- Repair tips may include replacing the spark plugs, ignition coil, or fuel injector for the affected cylinder, fixing any vacuum leaks, and ensuring proper fuel delivery.

5. Can driving with a P0303 code in a 2012 Nissan Altima Sedan cause further damage?

- Continuing to drive with a misfiring cylinder can potentially lead to damage to the catalytic converter, increased fuel consumption, and other engine-related issues.

6. How much does it typically cost to repair a number 3 cylinder misfire in a 2012 Nissan Altima Sedan?

- The cost of repairing a cylinder misfire can vary depending on the exact cause, but it may range from $100 to $500 or more, including parts and labor.

7. Is it safe to continue driving my 2012 Nissan Altima Sedan with a P0303 code until I can get it repaired?

- It is not recommended to drive the vehicle with a misfiring cylinder as it can lead to further damage and potential safety hazards. It's best to address the issue promptly.

8. Can a simple tune-up fix the P0303 code in a 2012 Nissan Altima Sedan?

- A tune-up, including replacing spark plugs and inspecting ignition components, may help resolve the misfire issue if the cause is related to these components.

9. Will resetting the OBDII code temporarily fix the P0303 issue in a 2012 Nissan Altima Sedan?

- Resetting the code may temporarily turn off the check engine light, but if the underlying issue causing the misfire is not addressed, the code is likely to return.

10. How long does it take to repair a number 3 cylinder misfire in a 2012 Nissan Altima Sedan?

- The repair time can vary depending on the specific cause of the misfire, but it may take anywhere from one to several hours to diagnose and fix the issue.