AutoCodes – Saturn – P0304 Saturn

P0304 Saturn Code - Cylinder 4 Misfire Detected

Quick Answer

A misfiring cylinder causes slight variations in the rotational speed of the crankshaft. 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 Saturn 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 26,509

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 13, 2022

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

A misfiring cylinder causes slight variations in the rotational speed of the crankshaft. The Engine Control Module (ECM) can detect these variations by closely monitoring the crankshaft position sensor signal. The signals of the camshaft position sensors are used to determine which cylinder is misfiring. If the ECM detects a misfire rate sufficient to cause emission levels to exceed mandated standards, the Diagnostic Trouble Code (DTC) will be set. Under certain driving conditions, a misfire rate can be high enough to cause the catalytic converter to overheat, damaging the converter. The Malfunction Indicator Lamp (MIL) flashes when the converter is overheating, damaging conditions are present, and the DTC is set. The DTC will be set when the ECM detects a crankshaft rotation speed variation indicating a single-cylinder misfire rate sufficient to cause emissions levels to exceed mandated standards.

OBDII Code P0304 Saturn - Cylinder 4 Misfire Detected - AutoCodes.com — P0304 Saturn Code - Cylinder 4 Misfire Detected

What does this mean?

What are the Possible Causes of the DTC P0304 Saturn?

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 Saturn?

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 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 need to be done to diagnose the problem, see "Possible Causes".

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0304 Saturn 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 Saturn Code

1. What are the common symptoms of OBDII code P0304 on a Saturn indicating a Cylinder 4 misfire?

Common symptoms include engine misfiring, rough idling, loss of power, and potential engine vibration.

2. What are the possible causes of a Cylinder 4 misfire detected in a Saturn triggering code P0304?

Potential causes may include faulty spark plugs, ignition coils, fuel injectors, vacuum leaks, compression issues, or problems with the engine control module.

3. How can I diagnose the cause of a Cylinder 4 misfire on my Saturn triggering OBDII code P0304?

Diagnostic steps may involve checking spark plugs and ignition coils, inspecting fuel injectors, performing a compression test, scanning for vacuum leaks, and using a diagnostic tool to monitor engine performance.

4. Can driving with OBDII code P0304 on a Saturn be harmful to the vehicle?

Continued driving with a Cylinder 4 misfire can potentially lead to further damage to the catalytic converter, increased fuel consumption, and other engine-related issues. It is recommended to address the issue promptly.

5. Are there any quick repair tips for resolving OBDII code P0304 on a Saturn related to Cylinder 4 misfire?

Quick repair tips may include checking and replacing faulty spark plugs, ignition coils, or fuel injectors, ensuring proper fuel and air mixture, and addressing any vacuum leaks.

6. Is it possible to reset OBDII code P0304 on a Saturn after addressing the Cylinder 4 misfire issue?

Once the underlying cause of the misfire is resolved, the OBDII code P0304 can be cleared using an OBDII scanner or by disconnecting the vehicle's battery for a short period.

7. How serious is a Cylinder 4 misfire detected in a Saturn causing OBDII code P0304?

A Cylinder 4 misfire should be addressed promptly to prevent potential damage to the engine and other components. Ignoring the issue can lead to more severe problems over time.

8. Can extreme weather conditions contribute to triggering OBDII code P0304 on a Saturn for a Cylinder 4 misfire?

Extreme weather conditions such as extreme cold or heat can sometimes exacerbate existing issues related to engine misfires, but they are not typically the primary cause of the problem.

9. Will a Cylinder 4 misfire causing OBDII code P0304 on a Saturn affect the vehicle's overall performance?

Yes, a Cylinder 4 misfire can impact the vehicle's performance by causing rough idling, reduced power, decreased fuel efficiency, and potential drivability issues.

10. How can regular maintenance help prevent issues like Cylinder 4 misfires triggering OBDII code P0304 on a Saturn?

Regular maintenance, including timely replacement of spark plugs, ignition components, and routine engine inspections, can help prevent issues like Cylinder 4 misfires and ensure optimal engine performance.