why does my Volkswagen Golf MK7.5 (2020-Present) have a check engine light with P0303 code?

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, torque wrench, compression tester, multimeter.
• Clear any stored error codes using the OBD-II scanner.
• Ensure the vehicle is parked on a level surface and the engine is cool.

2. Replace Spark Plug and/or Ignition Coil

• Sub-steps:
  1. Remove the engine cover (if applicable) using a socket set.
  2. Disconnect the ignition coil connector for cylinder 3.
  3. Remove the ignition coil using a socket set; inspect for damage.
  4. Remove the spark plug using a spark plug socket and inspect it for wear or carbon buildup.
  5. Install the new spark plug and torque it to the manufacturer’s specification (typically around 22 lb-ft).
  6. Install the new ignition coil and reconnect the electrical connector.

3. Test Fuel Injector

• Sub-steps:
  1. Disconnect the fuel injector connector for cylinder 3.
  2. Use a multimeter to check the resistance of the fuel injector; compare readings to manufacturer specifications.
  3. If the injector is faulty, replace it using a socket set.
  4. Reconnect the fuel injector connector.

4. Perform Compression Test

• Sub-steps:
  1. Remove the spark plug from cylinder 3.
  2. Insert the compression tester into the spark plug hole.
  3. Crank the engine for several seconds and note the compression reading.
  4. Compare the readings with manufacturer specifications; if low, further diagnosis is needed for possible internal engine issues.