how to fix P0302 misfire code on Toyota Highlander Third Generation (2014-2019)

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the negative battery terminal to ensure safety while working on electrical components.

2. Inspect and Replace Spark Plug

• Tools Required: Spark plug socket, ratchet, torque wrench, dielectric grease.
• Remove the ignition coil on cylinder 2 by unscrewing the bolts and disconnecting the electrical connector.
• Remove the spark plug using the spark plug socket and ratchet.
• Inspect the spark plug for wear or fouling. Replace it if necessary with a new spark plug that meets OEM specifications.
• Apply dielectric grease to the spark plug boot before reinstallation.

3. Check and Replace Ignition Coil

• Tools Required: Socket set, torque wrench.
• If the spark plug is in good condition, test the ignition coil by swapping it with a known good coil from another cylinder.
• If the misfire shifts to the other cylinder, replace the ignition coil for cylinder 2 with a new one.
• Torque the ignition coil to manufacturer specifications during reinstallation.

4. Inspect and Clean Fuel Injector

• Tools Required: Fuel injector cleaner, small brush, safety glasses.
• Remove the fuel injector for cylinder 2 by disconnecting the electrical connector and unscrewing any retaining clips.
• Clean the injector using a fuel injector cleaner or replace it if it’s clogged or malfunctioning.
• Reinstall the injector and ensure it is properly seated and connected.

5. Perform Compression Test

• Tools Required: Compression tester.
• If the misfire persists, conduct a compression test on cylinder 2.
• If the compression is low, further investigation is needed into the engine's internal components (valves, piston rings).