how to fix P0302 misfire code in Toyota Highlander Fourth Generation (2020-present)

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the negative battery terminal to ensure safety.
• Allow the engine to cool before starting work.

2. Replace Spark Plug

• Tools Required: Socket set, spark plug socket, torque wrench.
• Remove the ignition coil on cylinder 2 by unscrewing the retaining bolts and disconnecting the electrical connector.
• Use a spark plug socket to remove the old spark plug from cylinder 2.
• Inspect the new spark plug for proper gap size (typically around 0.043 inches for most Toyota engines).
• Install the new spark plug by hand, then torque it to the manufacturer’s specification (usually around 13 lb-ft).
• Reinstall the ignition coil and reconnect the electrical connector.

3. Test Ignition Coil

• Tools Required: Multimeter (optional for testing).
• Swap the ignition coil from cylinder 2 with another cylinder (e.g., cylinder 1).
• Clear the error codes using the OBD-II scanner.
• Start the engine and observe if the P0302 code returns or if the misfire moves to the cylinder where the coil was swapped.

4. Inspect Fuel Injector

• Tools Required: Fuel pressure gauge, injector cleaning kit (optional).
• Remove the fuel injector from cylinder 2.
• Check for blockages or leaks, and clean or replace the injector as necessary.
• Reinstall the fuel injector ensuring proper seating.

5. Perform Compression Test

• Tools Required: Compression tester.
• Remove the spark plug for cylinder 2.
• Insert the compression tester and crank the engine for a few seconds.
• Note the compression reading; it should be within the manufacturer's specifications (usually around 180 psi).
• If the compression is low, further engine diagnostics may be necessary.