how to resolve the P0301 code in my Toyota Highlander XU70 (2020-Present)?

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool before beginning work.

2. Inspect and Replace Spark Plug

• Remove the ignition coil cover (if applicable) using a socket set.
• Disconnect the ignition coil connector and remove the ignition coil for cylinder 1.
• Remove the spark plug using a spark plug socket and ratchet.
  • Inspect the spark plug for signs of wear or fouling.
  • If necessary, replace with a new spark plug (specifications: NGK IWF22 or equivalent, gap: 0.043 inches).
• Reinstall the spark plug and torque it to the manufacturer’s specifications (typically around 13 lb-ft).

3. Inspect and Replace Ignition Coil

• If the spark plug is in good condition, inspect the ignition coil.
• If damaged, replace the ignition coil with a new one (OEM parts recommended).
• Reconnect the ignition coil connector and reinstall the ignition coil.

4. Check Fuel Injector

• Remove the fuel rail (if necessary) to access the injector for cylinder 1.
• Inspect the fuel injector for clogs or leaks.
• Clean the injector if dirty or replace it if defective (OEM replacement recommended).
• Ensure proper reinstallation of the fuel rail and reconnect all lines.

5. Compression Test (if necessary)

• Remove the spark plug for cylinder 1.
• Insert a compression gauge into the spark plug hole.
• Crank the engine several times to get a reading.
  • Compare the reading to manufacturer specifications (typically around 150-200 psi).
• If compression is low, further investigation into engine internals may be necessary.