Are you having trouble starting your car? Is the check engine light on? If yes, you should identify the issue using an OBD-II scanner. On scanning, the scanner identified that the powertrain control module (PCM) logged the P0304 code. What can it be?
My car encountered the same issue recently. And I was worried about whether the P0304 engine code would significantly damage my car’s engine. This article will brief you on everything about this code, what causes it, and how you can fix it!
What does code P0304 mean?
It means “Cylinder 4 Misfire Detected.” Code P0304 indicates that Cylinder 4 of your car’s engine misfired numerous times for the PCM to notice and log it. You can usually observe this code with other rich/lean codes like the P0301 or P0118.
Can I drive with a P0304 code?
Ideally, most mechanics will ask you to stop driving as it’s a misfire code. As the code indicates a misfire on Cylinder 4, it will cause frequent engine misfires, indicating the combustion isn’t happening at the proper time as the timing is off. If you don’t diagnose and fix the issue, it may become a severe issue, leading to engine damage.
What causes code P0304?
The most common cause for engine code P0304 is a defective spark system. The following are other causes that can lead to this code.
- A defective distributor rotor or cap
- Valve leakage
- A defective fuel injector
- The throttle body is dirty
- An ignition coil or coil pack malfunction
- Vacuum leakage, lower fuel pressure, or a leaking intake gasket
Symptoms of a Code P0304
There are a number of signs that can help you easily diagnose this code.
- A flickering check engine light
- An engine is starting trouble
- Stalling
- Engine idling is rough
- Low power on uphill driving
- Excessive fuel usage
- Foul odor from exhaust
How do I fix code P0304?
You can easily fix a P0304 code through the following steps.
Look for extra DTCs
It is important to find out whether any further DTCs have been stored before diving into the diagnostic process. If this is the case, you must diagnose each additional code and correct them promptly.
Do a Freeze-Frame Data Analysis
You can also examine any freeze-frame data that you obtain during the DTC logging. This data can provide extra information useful throughout the diagnosis procedure. It includes the precise RPM range that you can mark as such misfires occur.
Examine the Ignition System Components Carefully
When one or more of an engine’s ignition system components fail, misfires occur. As a result, you must make sure to thoroughly inspect such components for failure or damage.
Spark plugs, spark plug wires, the engine’s distributor cap, and the rotor button are all components worth inspecting (if applicable). This is one way to fix the P0304 code.
Examine for the presence of a spark
If you identify no visible faults throughout the inspection, as mentioned earlier, the presence of a spark on the faulty cylinder must undergo verification. You may do this using an inline spark tester,
A lack of spark means your car needs to undergo suggests that more ignition system diagnosis, but the existence of a spark raises questions about other areas.
Check the fuel system for integrity and proper operation
You must also install a fuel pressure gauge in the fuel rail of the engine. The “Key On” fuel pressure readings should meet the P0304 or not exceed the car manufacturer’s specifications.
When trying to qualify an engine’s injectors, a bi-directional scan instrument will come in handy. You may need to ignite each injector with this type of scan tool. This releases a small amount of fuel into the combustion chamber.
Other ways to fix Ignition and fuel system Issues
Conduct a Compression Test
You may conduct a compression test of the cylinder to fix the P0304 code for damage. You should do this in case your car has no fuel concerns. Then, compare the results.
In addition, perform a “leak-down” test too. Differences in these tests are mostly due to internal mechanical concerns.
Cross-check the factory service information
It is important to review factory-specific service information for your specific car before starting any type of significant teardown. This information will highlight potential issues and provide torque values for performing the task.
If you’re not sure about your automotive skills, hiring a professional is probably advisable. First, identify the underlying issue that triggered the P0304 code if you are confident in your DIY abilities. Then, to determine the best solution to the problem, study online auto repair resources and instructions.
You can also get an ALLDATA single-vehicle membership, which will assist you in resolving any future automobile problems.
Before attempting to repair the issue yourselves, double-check your owner’s handbook.
What is the most common cause of the P0304 code?
The most common cause for this error code is a malfunctioning spark system.
All Your Questions Answered
Ideally, a faulty catalytic converter does not normally lead to a misfire code. However, a partially blocked catalytic converter might cause an engine to misfire. It happens because the exhaust gas flow becomes blocked, and old exhaust gas cannot exit the cylinder before the incoming air/fuel charge draws in.
Yes, having bad fuel injectors will cause the code to appear in your car.
Engine code P0304 on a Nissan Nurano indicates that Cylinder 4 of the car’s engine is misfiring. The PCM logs this code when it detects multiple misfires on Cylinder 4.
Code P0304 Ford implies that Cylinder 4 of the car’s engine is misfiring. The PCM logs this code when it senses numerous misfires in a cylinder.
P0304 engine code on a Honda engine indicates that a cylinder in the vehicle has misfired frequently enough for the PCM to detect.
It indicates that cylinder 4 of your Hyundai car’s engine has misfired frequently enough for your car’s PCM to detect and log it.
The error code means that the PCM detected many misfires on Cylinder 4 of your Mini Copper car.
P0304 engine code on a BMW indicates that the PCM detected multiple misfires on Cylinder 4 of your car.
P0304 code Ford F150 implies that the PCM sensed numerous misfires on Cylinder 4 of the car’s engine.
Sara Sam may not look like your typical car and finance expert, but don’t let that fool you. With over four years of experience in the industry, she knows all the ins and outs of cars, car insurance, and refinancing. You can trust Sara to help you navigate the often-confusing world of automobiles and financing.
