how to fix P0303 misfire code on Volkswagen Golf MK7.5 (2020-Present)

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the vehicle's battery to ensure safety.
• Ensure the engine is cool before starting work.

2. Replace Spark Plug

• Tools Required: Socket set, torque wrench, dielectric grease.
• Remove the ignition coil from cylinder 3:
  1. Disconnect the electrical connector from the ignition coil.
  2. Unbolt the ignition coil using the socket set and remove it.
• Remove the spark plug:
  1. Use a spark plug socket to unscrew and remove the spark plug.
• Inspect the spark plug:
  1. If it’s worn or fouled, replace it with a new spark plug that meets OEM specifications.
• Install the new spark plug:
  1. Apply a small amount of dielectric grease to the threads of the new spark plug.
  2. Torque the new spark plug to the manufacturer's specification (usually around 22 lb-ft).

3. Replace Ignition Coil (if necessary)

• If the ignition coil shows signs of damage:
  1. Install a new ignition coil by reversing the removal steps.
  2. Ensure the electrical connector clicks securely into place.

4. Check and Replace Fuel Injector (if necessary)

• If the fuel injector is found to be malfunctioning:
  1. Disconnect the fuel line and electrical connector from the injector.
  2. Remove the injector using appropriate tools.
  3. Install a new fuel injector, ensuring it is seated properly and reconnect the electrical connector.

5. Reassembly and Final Checks

• Reconnect the battery.
• Start the engine and check for any remaining error codes.
• Ensure the engine runs smoothly without misfiring.