what does it mean if my Toyota Highlander XU70 (2020-Present) has a P0301 code

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 shorts.

2. Inspect and Replace Spark Plug

• Sub-steps:
  1. Remove the engine cover (if applicable) using a socket set.
  2. Disconnect the ignition coil wiring harness from the cylinder 1 coil.
  3. Unbolt the ignition coil using a socket wrench and remove it.
  4. Use a spark plug socket to remove the spark plug from cylinder 1.
  5. Inspect the old spark plug for wear or damage. Replace it if necessary.
  6. Install the new spark plug and torque it to the manufacturer's specifications (typically around 13 lb-ft).
  7. Reinstall the ignition coil and reconnect the wiring harness.

3. Inspect and Test Ignition Coil

• Sub-steps:
  1. If the spark plug replacement does not resolve the issue, test the ignition coil using a multimeter.
  2. Check the resistance according to the specifications in the service manual.
  3. If the coil is faulty, replace it with a new one and ensure it is properly seated.

4. Inspect and Clean Fuel Injector

• Sub-steps:
  1. Disconnect the fuel injector connector for cylinder 1.
  2. Use a fuel injector cleaning kit to clean the injector or replace it if necessary.
  3. Reconnect the fuel injector and ensure it is properly seated.

5. Perform Compression Test

• Sub-steps:
  1. Remove the spark plug from cylinder 1.
  2. Insert a compression gauge into the spark plug hole.
  3. Crank the engine and note the compression reading.
  4. Compare the reading to the manufacturer's specifications. If it's low, further diagnosis for internal engine issues may be necessary.