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

Solution

1. Preparation

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

2. Inspect and Replace Ignition Components

• Tools Required: Socket set, torque wrench, spark plug socket, dielectric grease.
• Remove the engine cover if necessary to access the ignition coils.
• Disconnect the electrical connector from the ignition coil of cylinder 2.
• Remove the ignition coil using the socket set and inspect for cracks or damage.
• Remove the spark plug from cylinder 2 using the spark plug socket.
• Inspect the spark plug for wear or fouling; replace if necessary.
• Install a new spark plug and apply dielectric grease to the ignition coil connector.
• Reinstall the ignition coil, ensuring it is properly seated and torqued to manufacturer specifications.

3. Check and Replace Fuel Injector

• Tools Required: Fuel injector removal tool, safety goggles.
• Disconnect the fuel line and electrical connector from the fuel injector of cylinder 2.
• Remove the fuel injector using the removal tool and inspect for clogs or damage.
• Clean or replace the fuel injector as needed.
• Reinstall the fuel injector and reconnect the fuel line and electrical connector.

4. Compression Test

• Tools Required: Compression tester, appropriate adapters.
• Remove the spark plug from cylinder 2.
• Insert the compression tester into the spark plug hole.
• Crank the engine and note the compression reading; compare it to manufacturer specifications.
• If compression is low, further investigate potential internal engine issues.