how to fix P0300 misfire 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 12V battery before beginning repairs.
• Ensure the vehicle is parked on a flat surface and the parking brake is engaged.

2. Inspect and Replace Ignition Components

• Tools Required: Socket set, torque wrench, ignition coil puller (if applicable)
• Remove the engine cover if necessary.
• Disconnect the electrical connectors from the ignition coils.
• Remove the ignition coils by unscrewing the bolts and pulling them straight out.
• Inspect the spark plugs: remove and check for wear or carbon buildup.
  • Replace spark plugs if worn (check manufacturer specifications for gap).
• Reinstall new or cleaned ignition coils and securely connect electrical connectors.

3. Check Fuel System

• Tools Required: Fuel pressure gauge, multimeter
• Locate the fuel pump fuse and relay; check for proper operation.
• Connect a fuel pressure gauge to the fuel rail to check for adequate pressure (typically around 50-60 PSI).
• If pressure is low, inspect the fuel pump and replace if necessary.
• Check fuel injectors for proper operation using a multimeter or injector test tool.

4. Inspect for Vacuum Leaks

• Tools Required: Smoke machine (for testing), vacuum gauge
• Perform a smoke test to identify vacuum leaks in the intake manifold and associated hoses.
• Replace any damaged vacuum lines or gaskets.
• Ensure the throttle body is clean and free of debris.

5. Compression Test

• Tools Required: Compression tester
• Remove spark plugs and insert the compression tester into the spark plug holes.
• Crank the engine for several seconds and read the compression values.
• Compare the readings to the manufacturer specifications; low compression may indicate internal engine issues.