how to diagnose P0300 code on 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 tools and equipment: OBD-II scanner, multimeter, compression tester, smoke machine, and hand tools.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the negative battery terminal to ensure safety during repairs.

2. Inspect Ignition System

• Remove spark plugs:
  • Use a socket wrench to remove the spark plug cover.
  • Carefully unscrew and remove each spark plug.
• Inspect spark plugs for signs of wear, such as fouling or excessive wear.
• Check ignition coils:
  • Disconnect each coil connector.
  • Use a multimeter to test the resistance of the coils (usually around 0.5 to 1.5 ohms).
  • Replace any faulty coils.

3. Check for Vacuum Leaks

• Perform a smoke test:
  • Connect the smoke machine to the intake manifold.
  • Introduce smoke and observe for any leaks.
• Inspect all vacuum hoses visually and replace any that are cracked or disconnected.

4. Examine Fuel System

• Test fuel pressure:
  • Connect a fuel pressure gauge to the fuel rail.
  • Turn the ignition to the "ON" position without starting the engine and check the pressure (should be within manufacturer specifications).
• Inspect fuel injectors for proper operation:
  • Use a noid light to check for injector pulse.
  • Replace any malfunctioning injectors.

5. Perform Compression Test

• Remove spark plugs again if they were not already removed.
• Insert compression tester into each cylinder.
• Crank the engine and record the compression readings.
• Compare results against manufacturer specifications (typically between 150-200 psi).