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Home/Cars/Honda/Accord/11th Gen (2023-Present)/how to fix P0304 misfire code in Honda Accord Eleventh Generation (2023-present)

how to fix P0304 misfire code in Honda Accord Eleventh Generation (2023-present)

Honda Accord 11th Gen (2023-Present)

Error Codes
Severity: highDifficulty: mediumError Code: P03042-4 hours
4 min read
640 words

⚠️ Safety Warning

This issue requires immediate attention. If you are not experienced with automotive repairs, consult a professional mechanic. Working on critical systems can be dangerous.

Problem Statement

Learn how to diagnose and fix P0304 cylinder 4 misfire in Honda Accord. Step-by-step guide with diagnostic procedures and repair instructions.

Error Code
P0304
Affected Component
Engine
Estimated Time
2-4 hours

Safety Warnings

  • ⚠Disconnect the negative battery terminal before working on electrical components.
  • ⚠Allow the engine to cool before opening any components.

Symptoms

  • •Check engine light illuminated
  • •Engine rough idle
  • •Decreased acceleration or power
  • •Poor fuel economy
  • •Engine stalling or hesitation during acceleration

Diagnostic Steps

  1. 1Scan for error codes using an OBD-II scanner to confirm the P0304 code.
  2. 2Inspect the spark plug and ignition coil in cylinder 4 for wear or damage.
  3. 3Check the fuel injector for cylinder 4 for proper operation and fuel delivery.
  4. 4Conduct a compression test on cylinder 4 to assess engine health.
  5. 5Inspect wiring and connectors related to the ignition system and fuel injector for faults.
  6. 6Examine the intake manifold for vacuum leaks that could affect cylinder 4 performance.

Solution

Solution

1. Preparation

  • Gather necessary tools and parts.
  • Disconnect the negative battery terminal to ensure safety while working.
  • Allow the engine to cool before proceeding.

2. Inspect and Replace Spark Plug

  • Tools Required: Socket set, torque wrench, gap gauge.
  • Remove the ignition coil cover (if applicable).
  • Disconnect the ignition coil connector and remove the ignition coil from cylinder 4.
  • Remove the spark plug using a spark plug socket.
  • Inspect the spark plug for wear or damage, and replace if necessary.
  • Set the gap on the new spark plug to manufacturer specifications (typically 0.043 inches).
  • Install the new spark plug and torque to the manufacturer's specifications (usually 13 lb-ft).

3. Check and Replace Ignition Coil

  • If the spark plug is fine, inspect the ignition coil.
  • Tools Required: Socket set.
  • Remove the ignition coil from cylinder 4.
  • Test the ignition coil with a multimeter to ensure it meets resistance specifications.
  • Replace the ignition coil if it is faulty.
  • Reinstall the ignition coil and reconnect the connector.

4. Inspect and Replace Fuel Injector

  • If ignition components are functioning correctly, test the fuel injector.
  • Tools Required: Fuel pressure gauge, socket set.
  • Remove the fuel injector connector and use a multimeter to check for voltage.
  • If voltage is present, remove the fuel injector.
  • Inspect for clogs or damage and replace if necessary.
  • Reinstall the fuel injector and reconnect the electrical connector.

5. Perform Compression Test

  • If the issue persists, perform a compression test on cylinder 4.
  • Tools Required: Compression tester.
  • Remove the spark plug from cylinder 4.
  • Insert the compression tester into the spark plug hole and crank the engine.
  • Record the compression reading; it should be within manufacturer specifications (usually around 180 psi).
  • If compression is low, inspect for possible internal engine issues such as valve problems or head gasket failure.

Verification

After completing the repair, verify that the issue has been resolved:

  • ✓Test the affected component to ensure it functions correctly
  • ✓Check for any error codes or warning lights
  • ✓Monitor the vehicle for a few days to ensure the issue does not recur

Prevention Tips

To prevent this issue from occurring again:

  • •Follow the manufacturer's recommended maintenance schedule
  • •Address warning signs early before they develop into major issues
  • •Use quality parts and fluids recommended for your vehicle
  • •Keep detailed records of all repairs and maintenance

Tools & Equipment Required

  • •OBD-II scanner
  • •Socket set
  • •Torque wrench
  • •Multimeter
  • •Compression tester
  • •Fuel pressure gauge

Parts Required

  • •Spark plug (for cylinder 4)
  • •Ignition coil (for cylinder 4)
  • •Fuel injector (for cylinder 4) if needed

Additional Information

Error Code
P0304
Affected Component
Engine
Estimated Time
2-4 hours
Difficulty
medium
Severity
high
Tools Required
6 items
Parts Required
3 items

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