how to diagnose a P0303 code on my Volkswagen Golf MK7 (2015-2019)

Solution

1. Preparation

• Gather required tools and parts.
• Park the vehicle on a level surface and engage the parking brake.
• Disconnect the negative battery terminal to ensure safety.

2. Inspect and Replace Spark Plug

1. Locate the spark plug for cylinder 3 (consult the vehicle manual for position).
2. Remove the ignition coil by unscrewing the retaining bolts and gently pulling it out.
3. Use a socket wrench to remove the spark plug from cylinder 3.
4. Inspect the spark plug for wear; replace it if it shows signs of damage (e.g., worn electrodes, carbon deposits).
5. Install a new spark plug, tightening it to the manufacturer’s specified torque (typically around 22 ft-lbs).

3. Inspect and Replace Ignition Coil

1. If the spark plug is in good condition, test the ignition coil for cylinder 3.
2. If found faulty, disconnect the electrical connector and unscrew the ignition coil from the engine.
3. Install the new ignition coil securely, reconnecting the electrical connector.

4. Check and Replace Fuel Injector

1. Remove the fuel rail if necessary to access the fuel injector for cylinder 3.
2. Disconnect the fuel injector electrical connector.
3. Remove the old fuel injector by unscrewing or unclipping it from the rail.
4. Install the new fuel injector, ensuring proper seating and connection.

5. Reassemble and Reconnect

1. Reattach the ignition coil and reconnect its electrical connector.
2. Ensure all connectors are secure and there are no loose wires.
3. Reconnect the negative battery terminal.