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

Solution

1. Preparation

• Ensure the engine is turned off and cool before starting work.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Spark Plug

• Tools Required: Socket set, spark plug socket, torque wrench
• Remove the engine cover if necessary.
• Locate the spark plug in cylinder 2.
• Use the spark plug socket to remove the old spark plug.
• Inspect the spark plug for signs of wear (carbon buildup, oil, or extreme wear).
• If worn, replace it with a new spark plug, ensuring it matches the specifications provided by the manufacturer.
• Torque the new spark plug to the manufacturer’s specification (usually around 13-15 lb-ft).

3. Check and Replace Ignition Coil

• Tools Required: Socket set, multimeter
• Disconnect the electrical connector from the ignition coil in cylinder 2.
• Remove the ignition coil using the socket set.
• Use the multimeter to test the coil for resistance; consult the repair manual for specific values.
• If the coil fails the test, replace it with a new ignition coil.
• Reinstall the ignition coil and reconnect the electrical connector.

4. Inspect Fuel Injector

• Tools Required: Noid light or fuel pressure gauge
• Disconnect the fuel injector connector for cylinder 2.
• Use a noid light to check for injector pulse; it should flash with engine cranking.
• If there’s no pulse, check wiring and replace the connector if necessary.
• If pulse is present, use a fuel pressure gauge to verify fuel delivery.
• If the injector is faulty, replace it with a new one.

5. Compression Test (if necessary)

• Tools Required: Compression tester
• Remove the spark plug from cylinder 2.
• Insert the compression tester into the spark plug hole.
• Crank the engine several times and record the compression reading.
• If the compression is below manufacturer specifications, further investigation into the engine’s internal components may be necessary.