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

Solution

1. Preparation

• Gather tools and parts needed for repairs.
• Disconnect the negative battery terminal to ensure safety while working on electrical components.

2. Inspect and Replace Spark Plug

• Remove the ignition coil from cylinder 2:
  • Use a socket set to remove the mounting bolts.
  • Carefully lift the coil straight up to avoid damaging the connector.
• Remove the spark plug using a spark plug socket.
• Inspect the spark plug for wear, carbon deposits, or damage. Replace if necessary with a manufacturer-specified spark plug.
• Reinstall the spark plug and ignition coil, ensuring proper torque (typically around 13 ft-lbs for spark plugs).

3. Test and Replace Fuel Injector

• Disconnect the fuel injector connector for cylinder 2.
• Use a multimeter to check the injector's resistance; replace if outside manufacturer specifications.
• If the injector is faulty, remove it using an injector puller.
• Install the new fuel injector and reconnect the fuel line, ensuring no leaks.

4. Perform Compression Test

• Remove all spark plugs to allow for accurate compression readings.
• Insert the compression gauge into the cylinder 2 spark plug hole.
• Crank the engine and record the compression reading. Compare with manufacturer specifications.
• If compression is low, further diagnostics may be needed for internal engine problems.

5. Check for Vacuum Leaks

• With the engine running, use a smoke machine or carburetor cleaner around the intake manifold and vacuum hoses.
• Listen for changes in engine RPM, indicating a vacuum leak.
• Repair or replace any faulty hoses or gaskets as necessary.