my Toyota Highlander XU70 (2020-Present) has a check engine light and P0301 code, what does it mean?

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the battery to prevent electrical shocks.

2. Inspect and Replace Spark Plug

• Tools Required: Socket set, torque wrench, spark plug socket.
• Remove the ignition coil from cylinder 1:
  1. Unplug the electrical connector from the ignition coil.
  2. Remove the bolts securing the ignition coil and lift it out.
• Remove the spark plug using a spark plug socket.
• Inspect the spark plug for wear. Replace it if it shows signs of damage (e.g., burned electrode, excessive carbon buildup).
• Install a new spark plug using the manufacturer's torque specification (usually around 13 ft-lbs).

3. Check and Replace Ignition Coil

• If the spark plug is fine, test the ignition coil:
  1. Using a multimeter, check the resistance of the ignition coil according to manufacturer specifications.
  2. If the coil is faulty, replace it with a new one.
• Reinstall the ignition coil and reconnect the electrical connector.

4. Inspect Fuel Injector

• If the ignition system is functioning correctly, check the fuel injector:
  1. Remove the fuel rail to access the injector.
  2. Inspect the injector for clogs or leaks.
  3. Test the injector's electrical circuit with a multimeter.
  4. Replace the fuel injector if it is defective.

5. Compression Test

• If misfire persists, perform a compression test on cylinder 1:
  1. Remove the spark plug.
  2. Insert the compression tester and crank the engine.
  3. Note the reading; it should be within the manufacturer's specifications (usually around 120-200 psi).
  4. If compression is low, further investigate for potential internal engine issues.