my Tesla Outback has a check engine light with code P0304, what does that mean?

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

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, torque wrench, compression tester, fuel injector cleaning kit.
• Safety Warnings: Disconnect the battery before working on electrical systems. Allow the engine to cool before proceeding.

2. Inspect and Replace Spark Plug

• Remove the ignition coil from cylinder 4.
• Use a socket to remove the spark plug from cylinder 4.
• Inspect the spark plug for carbon buildup or damage; replace if necessary.
• Torque the new spark plug to the manufacturer’s specifications (typically around 13 lb-ft).
• Reinstall the ignition coil.

3. Check and Replace Ignition Coil (if needed)

• If the spark plug is in good condition, inspect the ignition coil for cracks or resistance issues.
• If replacement is necessary, use the socket to remove the faulty coil.
• Install the new ignition coil and ensure it is seated properly.

4. Inspect Fuel Injector

• Disconnect the fuel injector connector for cylinder 4.
• Use a multimeter to test the injector’s resistance (typically around 12-16 ohms).
• If the injector is faulty, remove it using a fuel injector puller.
• Replace with a new injector and reconnect the electrical connector.

5. Perform Compression Test

• Remove the spark plug from cylinder 4 and insert the compression tester.
• Crank the engine for a few seconds and record the compression reading.
• Compare the reading with manufacturer specifications; replace piston rings or valves if compression is low.