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

Solution

1. Preparation

• Gather all necessary tools and parts.
• Ensure the vehicle is in a safe, level area.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Spark Plug

• Tools Required: Socket set, torque wrench, gap gauge
• Remove the ignition coil covering (if applicable).
• Disconnect the electrical connector from the ignition coil.
• Remove the ignition coil from cylinder 2 using a socket.
• Remove the spark plug using a spark plug socket.
• Inspect the spark plug for wear, carbon buildup, or damage; replace if necessary.
• Install the new spark plug, ensuring it is gapped correctly (typically around 0.044 inches for most Toyota engines).
• Torque the spark plug to manufacturer's specifications (usually around 13 lb-ft).
• Reinstall the ignition coil and reconnect the electrical connector.

3. Inspect and Replace Ignition Coil (if necessary)

• If the spark plug is fine, check the ignition coil for continuity and resistance using a multimeter.
• If faulty, replace the ignition coil with a new one.
• Reinstall the ignition coil and reconnect the electrical connector.

4. Inspect and Replace Fuel Injector (if necessary)

• If the ignition coil is functioning properly, check the fuel injector for cylinder 2.
• Disconnect the fuel line (use caution and follow safety procedures).
• Remove the fuel injector and inspect for clogs or damage; clean or replace if necessary.
• Reinstall the fuel injector ensuring it is seated properly and reconnect the fuel line.

5. Perform a Compression Test (if misfire persists)

• Remove the spark plug from cylinder 2 and install a compression gauge.
• Crank the engine several times to get a compression reading.
• Compare the reading to the specifications (usually around 180 psi for a healthy engine).
• If compression is low, further engine diagnostics may be needed.