AutoCodes – Volvo – P0304 Volvo

P0304 Volvo Code - Cylinder 4 Misfire Detected

Quick Answer

When a misfire occurs, engine speed will fluctuate. Common causes include Faulty Spark Plug #4, Clogged or faulty Fuel Injector #4, Faulty Ignition Coil #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 Volvo indicates Cylinder 4 Misfire Detected.
Common causes: Common causes include Faulty Spark Plug #4, Clogged or faulty Fuel Injector #4, Faulty Ignition Coil #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 33,056

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 Jun 14, 2020

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0304 Volvo 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 Volvo - Cylinder 4 Misfire Detected - AutoCodes.com — P0304 Volvo Code - Cylinder 4 Misfire Detected

What does this mean?

What are the Possible Causes of the DTC P0304 Volvo?

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 Volvo?

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 Volvo 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 P0304 Volvo Code

1. What are common symptoms of OBDII code P0304 in a Volvo indicating a cylinder 4 misfire?

- Common symptoms include engine rough idling, loss of power, noticeable engine vibrations, and potential fuel odor.

2. What are some possible causes of a cylinder 4 misfire detected in a Volvo triggering code P0304?

- Possible causes include faulty spark plugs, ignition coil issues, fuel injector problems, vacuum leaks, compression issues, or wiring harness issues.

3. How can I diagnose the cause of a cylinder 4 misfire in my Volvo with code P0304?

- Diagnose by checking spark plugs, ignition coils, fuel injectors, vacuum lines, compression levels, and inspecting the wiring harness for any damage.

4. Can a dirty or clogged fuel injector cause a cylinder 4 misfire in a Volvo with code P0304?

- Yes, a dirty or clogged fuel injector can cause an insufficient fuel supply to cylinder 4, leading to a misfire and triggering code P0304.

5. Is it safe to drive my Volvo with an active OBDII code P0304 related to a cylinder 4 misfire?

- It is not recommended to drive the vehicle with a misfire as it can cause further damage to the engine components. Seek repairs promptly.

6. How can I fix a cylinder 4 misfire detected in my Volvo showing OBDII code P0304?

- Fix the issue by addressing the root cause, such as replacing faulty spark plugs, ignition coils, fuel injectors, or repairing any vacuum leaks or wiring issues.

7. Can a bad ignition coil be the reason for a cylinder 4 misfire in a Volvo with code P0304?

- Yes, a faulty ignition coil can lead to a weak or inconsistent spark to cylinder 4, causing a misfire and triggering the OBDII code P0304.

8. What is the typical cost to repair a cylinder 4 misfire in a Volvo with OBDII code P0304?

- The cost of repair can vary depending on the exact cause of the misfire, but it may range from $100 to $500 for parts and labor.

9. Will resetting the OBDII code P0304 in my Volvo clear the cylinder 4 misfire issue?

- Resetting the code without addressing the underlying cause will not fix the misfire problem. It is essential to diagnose and repair the issue first.

10. Can a cylinder 4 misfire detected in a Volvo with code P0304 lead to failed emissions testing?

- Yes, a misfire can affect the vehicle's emissions output, potentially causing it to fail emissions testing. It is recommended to address the issue before testing.