how to troubleshoot P0302 misfire code on Tesla Model 3 Highland (2024-present)

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a flat surface and the parking brake is engaged.
• Disconnect the negative terminal of the battery for safety.

2. Inspect and Replace Spark Plug

• Sub-steps:
  1. Remove the engine cover if applicable.
  2. Disconnect the ignition coil connector for cylinder 2.
  3. Remove the ignition coil using a socket wrench.
  4. Extract the spark plug with a spark plug socket.
  5. Inspect the spark plug for wear or fouling; replace if necessary.
  6. Install a new spark plug (torque to manufacturer specifications, typically 15-20 ft-lbs).
  7. Reattach the ignition coil and connector.

3. Inspect and Replace Fuel Injector

• Sub-steps:
  1. Disconnect the fuel injector harness for cylinder 2.
  2. Remove the fuel rail assembly if necessary to access the injector.
  3. Pull out the fuel injector and inspect for blockage or damage.
  4. Replace with a new fuel injector if needed.
  5. Reinstall the fuel rail and ensure all connections are secure.

4. Compression Test

• Sub-steps:
  1. Reconnect the battery.
  2. Remove the spark plug from cylinder 2.
  3. Insert the compression gauge and crank the engine for 5-10 seconds.
  4. Record the compression reading; it should be within the manufacturer’s specifications (typically 180-220 psi).
  5. If the reading is low, further diagnosis is needed for potential internal engine issues.

5. Reconnect and Test

• Sub-steps:
  1. Reconnect all components and wiring harnesses.
  2. Clear the trouble codes using the OBD-II scanner.
  3. Start the engine and monitor for any misfire codes.

Tools Required:

• OBD-II scanner
• Socket set
• Torque wrench
• Spark plug socket
• Compression gauge

Parts Required:

• Spark plug(s)
• Ignition coil (if damaged)
• Fuel injector (if faulty)

Estimated Repair Time: 2-4 hours

Safety Warnings:

• Disconnect the battery before working on electrical components.
• Allow the engine to cool before performing any work on the ignition system.