how to diagnose P0300 code in Tesla Model S Plaid/Refresh (2021-present)

Learn how to diagnose and fix P0300 engine misfire in Tesla Model S Plaid. Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the vehicle's battery to ensure safety.
• Ensure the vehicle is on a flat surface and securely raised if needed.

2. Inspect and Replace Spark Plugs

• Sub-steps:
  1. Remove the engine cover if applicable.
  2. Disconnect the wiring harness from the ignition coils.
  3. Unbolt and remove the ignition coils.
  4. Remove the old spark plugs using a spark plug socket.
  5. Inspect old spark plugs for wear (replace if necessary).
  6. Install new spark plugs to manufacturer specifications (usually 12-16 ft-lbs torque).
  7. Reinstall ignition coils and reconnect wiring harness.

3. Check and Replace Ignition Coils

• Sub-steps:
  1. If misfire persists after spark plug replacement, remove the ignition coils.
  2. Inspect each coil for cracks or carbon tracking.
  3. Replace any faulty ignition coils with OEM or high-quality aftermarket parts.
  4. Reinstall the ignition coils and reconnect connectors.

4. Test Fuel System Pressure

• Sub-steps:
  1. Connect a fuel pressure gauge to the fuel rail (if accessible).
  2. Turn the ignition on without starting the engine and check the pressure reading against specifications.
  3. If the reading is low, inspect the fuel pump and fuel filter for issues.
  4. Replace the fuel pump or filter as necessary.

5. Inspect for Vacuum Leaks

• Sub-steps:
  1. With the engine running, use a smoke machine or spray soapy water on intake and vacuum lines.
  2. Look for any visible signs of air leaks (bubbles or smoke).
  3. Repair or replace any damaged hoses or gaskets found.