how to fix P0304 misfire code in Porsche Cayenne E3 (2018-Present)

Learn how to diagnose and fix P0304 cylinder 4 misfire in Porsche Cayenne E3. Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shock.

2. Inspect and Replace Spark Plug

• Tools Required: Socket set, torque wrench, spark plug socket.
• Remove the ignition coil from cylinder 4 by unscrewing it.
• Use a spark plug socket to remove the spark plug.
• Inspect the spark plug for wear or fouling; replace if necessary with OEM specifications.
• Torque the new spark plug to the manufacturer’s specifications (typically around 25 Nm or 18 lb-ft).
• Reinstall the ignition coil securely.

3. Inspect and Replace Ignition Coil

• If the spark plug is in good condition, visually inspect the ignition coil for cracks or damage.
• Disconnect the electrical connector from the ignition coil.
• Remove the ignition coil from the cylinder.
• Install the new ignition coil, ensuring it is seated properly.
• Reconnect the electrical connector.

4. Test Fuel Injector

• Tools Required: Noid light or fuel injector tester.
• Disconnect the fuel injector connector on cylinder 4.
• Connect the noid light to the injector connector and crank the engine.
• Ensure the noid light flashes, indicating the injector is receiving a signal. If not, inspect the wiring and ECM for faults.
• If the injector is malfunctioning, remove and replace it with a new one.