OBD-II DTC P0304 – Cylinder 3 Misfire Detected
DTC P0304 meaning
DTC P0304 indicates that the Engine Control Module (ECM) has detected a misfire in cylinder number 3. A misfire occurs when the air-fuel mixture in the cylinder fails to ignite properly, leading to incomplete combustion. This can result in poor engine performance, increased emissions, and potential damage to the engine if not addressed.
DTC P0304 symptoms
Common symptoms associated with DTC P0304 include:
- Rough idling or engine shaking
- Decreased engine power and acceleration
- Increased fuel consumption
- Illuminated check engine light
- Unusual engine noises, such as backfiring
DTC P0304 causes
Several factors can lead to a misfire in cylinder 3, including:
- Faulty spark plug or spark plug wire
- Defective fuel injector
- Vacuum leaks affecting air-fuel mixture
- Compression issues in the cylinder
- Faulty ignition coil
- Engine control module (ECM) issues
DTC P0304 seriousness
DTC P0304 can be serious if left unresolved. Continuous misfiring can lead to:
- Increased emissions, potentially failing emissions tests
- Damage to the catalytic converter due to unburned fuel
- Engine overheating and further mechanical failures
It is advisable to address this code promptly to avoid more extensive repairs.
How to diagnose DTC P0304
To diagnose DTC P0304, follow these steps:
- Use an OBD-II scanner to confirm the code and check for additional codes.
- Inspect the spark plug and ignition coil for cylinder 3.
- Check the fuel injector operation for cylinder 3.
- Perform a compression test on cylinder 3.
- Look for vacuum leaks around the intake manifold and hoses.
How to fix DTC P0304 step-by-step instructions
To fix DTC P0304, follow these steps:
- Replace the spark plug and/or ignition coil for cylinder 3 if faulty.
- Clean or replace the fuel injector for cylinder 3 if it is clogged or malfunctioning.
- Repair any vacuum leaks found during inspection.
- Perform a compression test and address any issues if compression is low.
- Clear the DTC using an OBD-II scanner and test drive the vehicle to ensure the issue is resolved.
How to erase DTC P0304
To erase DTC P0304, follow these steps:
- Connect an OBD-II scanner to the vehicle’s diagnostic port.
- Turn on the ignition without starting the engine.
- Navigate to the “Erase Codes” or “Clear DTCs” option on the scanner.
- Confirm the action to clear the codes.
- Disconnect the scanner and start the engine to verify that the check engine light is off.
Recommended tools for OBD-II diagnostics
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