how to fix P0304 code in Honda CR-V Fifth Generation (2017-2022)

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, socket set, torque wrench, compression tester, fuel injector cleaner.
• Ensure the vehicle is on a flat surface and the engine is cool. Disconnect the negative battery terminal to prevent electrical shorts.

2. Replace Spark Plug

• Sub-steps:
  1. Remove the engine cover (if applicable) using a socket set.
  2. Disconnect the ignition coil connector for cylinder 4.
  3. Remove the ignition coil using a socket set.
  4. Remove the spark plug using a spark plug socket.
  5. Inspect the old spark plug; replace if worn or damaged.
  6. Install the new spark plug hand-tight, then torque to the manufacturer's specifications (usually around 13-16 lb-ft).
  7. Reinstall the ignition coil and connector.

3. Test and Replace Ignition Coil (if necessary)

• Sub-steps:
  1. Use a multimeter to test the resistance of the ignition coil according to specifications (typically 0.4-2 ohms for primary).
  2. If the coil is faulty, replace it with a new one.
  3. Reconnect the ignition coil and ensure it’s properly seated.

4. Inspect and Clean Fuel Injector

• Sub-steps:
  1. Disconnect the fuel injector connector for cylinder 4.
  2. Remove the fuel injector using the appropriate tools (may require fuel rail removal).
  3. Clean the injector using a fuel injector cleaner.
  4. Reinstall the injector and reconnect the fuel injector connector.

5. Perform Compression Test

• Sub-steps:
  1. Remove the spark plug from cylinder 4.
  2. Insert the compression tester and crank the engine.
  3. Record the compression reading; it should match the manufacturer’s specifications (usually around 180-200 psi).
  4. If compression is low, further engine diagnostics may be necessary (valve issues, gasket leaks).