AutoCodes – Honda – P0304 2010 Honda Accord

P0304 2010 Honda Accord Code - Cylinder Number 4 Misfire Detected

Quick Answer

When a misfire occurs, engine speed will fluctuate. Common causes include Valve adjustment, Faulty Spark Plug #4, Clogged or faulty Fuel Injector #4. 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: P0304 2010 Honda Accord indicates Cylinder Number 4 Misfire Detected.
Common causes: Common causes include Valve adjustment, Faulty Spark Plug #4, Clogged or faulty Fuel Injector #4.
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 10,757

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 Apr 09, 2019

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0304 2010 Honda Accord 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.

OBDII Code P0304 2010 Honda Accord - Cylinder Number 4 Misfire Detected - AutoCodes.com — P0304 2010 Honda Accord Code - Cylinder Number 4 Misfire Detected

What does this mean?

What are the Possible Causes of the DTC P0304 2010 Honda Accord?

Valve adjustment
Faulty Spark Plug #4
Clogged or faulty Fuel Injector #4
Faulty Ignition Coil #4
Fuel Injector #4 harness is open or shorted
Fuel Injector #4 circuit poor electrical connection
Ignition Coil #4 harness is open or shorted
Ignition Coil #4 circuit poor electrical connection
Insufficient cylinder 4 compression
Incorrect fuel pressure
Intake air leak

How to Fix the DTC P0304 2010 Honda Accord?

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 P0304 code means that the cylinder 4 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 4. If the problem persists more tests needs to be done to diagnose problem, see "Possible Causes"

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0304 2010 Honda Accord 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 P0304 2010 Honda Accord code?

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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 P0304 2010 Honda Accord Code

1. What are the common symptoms of OBDII code P0304 in a 2010 Honda Accord?

- Common symptoms include engine misfires, rough idle, loss of power, and potentially increased fuel consumption.

2. What are the possible causes of a cylinder number 4 misfire in a 2010 Honda Accord?

- Common causes can include faulty spark plugs, ignition coils, fuel injectors, vacuum leaks, or issues with the engine's compression.

3. How can I diagnose the cylinder number 4 misfire in my 2010 Honda Accord?

- Diagnose the issue by checking the spark plug, ignition coil, fuel injector, and performing a compression test to identify the root cause of the misfire.

4. Can a dirty or clogged fuel injector cause OBDII code P0304 in a 2010 Honda Accord?

- Yes, a dirty or clogged fuel injector can disrupt the fuel delivery to cylinder number 4, leading to a misfire and triggering the OBDII code P0304.

5. Is it safe to drive my 2010 Honda Accord with OBDII code P0304?

- It is not recommended to drive your vehicle with a cylinder misfire as it can cause further damage to the engine and reduce fuel efficiency.

6. How can I repair OBDII code P0304 in my 2010 Honda Accord?

- Repair options may include replacing the spark plugs, ignition coils, fuel injectors, or addressing any vacuum leaks to resolve the misfire issue.

7. Can a bad ignition coil cause a cylinder number 4 misfire in a 2010 Honda Accord?

- Yes, a faulty ignition coil can lead to a weak spark or no spark at all in cylinder number 4, resulting in a misfire and triggering the OBDII code P0304.

8. Will OBDII code P0304 clear itself in a 2010 Honda Accord?

- The code may clear itself temporarily after a few driving cycles if the issue was intermittent, but it's recommended to diagnose and repair the underlying problem.

9. How important is it to address OBDII code P0304 promptly in a 2010 Honda Accord?

- It is crucial to address the misfire issue promptly to prevent potential damage to the engine, catalytic converter, and to ensure optimal performance and fuel efficiency.

10. Can a low engine compression cause cylinder number 4 misfire in a 2010 Honda Accord?

- Yes, low engine compression in cylinder number 4 can lead to a misfire as the proper air-fuel mixture is not achieved, triggering the OBDII code P0304.