AutoCodes – Infiniti – P0305 Infiniti

P0305 Infiniti Code - Number 5 Cylinder Misfire Detected

Quick Answer

When a misfire occurs, engine speed will fluctuate. Common causes include Faulty spark plug 5, Clogged or faulty fuel injector 5, Faulty ignition coil 5. 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: P0305 Infiniti indicates Number 5 Cylinder Misfire Detected.
Common causes: Common causes include Faulty spark plug 5, Clogged or faulty fuel injector 5, Faulty ignition coil 5.
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 28,006

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 09, 2022

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0305 Infiniti 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 #5 is misfiring.

OBDII Code P0305 Infiniti - Number 5 Cylinder Misfire Detected - AutoCodes.com — P0305 Infiniti Code - Number 5 Cylinder Misfire Detected

What does this mean?

What are the Possible Causes of the DTC P0305 Infiniti?

Faulty spark plug 5
Clogged or faulty fuel injector 5
Faulty ignition coil 5
Fuel injector 5 harness is open or shorted
Fuel injector 5 circuit poor electrical connection
Ignition coil 5 harness is open or shorted
Ignition coil 5 circuit poor electrical connection
Insufficient cylinder 5 compression
Incorrect fuel pressure
Intake air leak

How to Fix the DTC P0305 Infiniti?

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 P0305 code means that cylinder #5 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 #5. 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 P0305 Infiniti 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 P0305 Infiniti code?

Need more information on how to fix the P0305 Infiniti code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P0305 Infiniti code diagnosed by a professional: Find a repair shop in your area

Information for Specific Infiniti Models

P0305 2003 Infiniti G35 — Number 5 Cylinder Misfire Detected
P0305 2004 Infiniti G35 — Number 5 Cylinder Misfire Detected
P0305 2005 Infiniti G35 — Number 5 Cylinder Misfire Detected
P0305 2006 Infiniti G35 — Number 5 Cylinder Misfire Detected

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 P0305 Infiniti Code

1. What are the common symptoms of OBDII code P0305 in an Infiniti?

- Common symptoms of P0305, indicating a misfire in the number 5 cylinder, include rough idling, loss of power, and increased fuel consumption.

2. What are the potential causes of the number 5 cylinder misfire in an Infiniti?

- The misfire detected in cylinder number 5 can be caused by issues such as a faulty ignition coil, spark plug, fuel injector, or vacuum leak.

3. How can I diagnose the cause of the number 5 cylinder misfire in my Infiniti?

- To diagnose the misfire, you can perform a visual inspection of the ignition components, test the spark plug and ignition coil, check for vacuum leaks, and use a scan tool to monitor live data.

4. Is it safe to drive my Infiniti with OBDII code P0305 present?

- It's not recommended to drive your Infiniti with a cylinder misfire as it can lead to further damage to the engine and other components. It's best to address the issue promptly.

5. How can I repair OBDII code P0305 in my Infiniti?

- Repairing P0305 involves identifying and replacing the faulty component causing the misfire, such as the ignition coil, spark plug, or fuel injector in the number 5 cylinder.

6. Can a dirty fuel injector cause OBDII code P0305 in an Infiniti?

- Yes, a dirty or clogged fuel injector can disrupt the fuel delivery to the number 5 cylinder, leading to a misfire and triggering code P0305.

7. Will a bad oxygen sensor trigger code P0305 in an Infiniti?

- While a faulty oxygen sensor can affect the air-fuel mixture, it is less likely to directly cause a misfire in a specific cylinder like the one indicated by code P0305.

8. How important is it to address OBDII code P0305 promptly in an Infiniti?

- Promptly addressing code P0305 is crucial to prevent further damage to the engine, maintain optimal performance, and ensure fuel efficiency in your Infiniti.

9. Can a vacuum leak lead to OBDII code P0305 in an Infiniti?

- Yes, a vacuum leak near the number 5 cylinder can disrupt the air-fuel mixture, potentially causing a misfire and triggering code P0305.

10. Should I reset the OBDII code P0305 after repairing the issue in my Infiniti?

- After repairing the cause of the misfire indicated by code P0305, it is recommended to clear the code using a scan tool to reset the Check Engine Light and monitor for any recurring issues.