how to fix P0301 code on Toyota Highlander XU70 (2020-Present)

Solution

1. Preparation

• Gather all necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Spark Plug

• Tools Required: Socket set, torque wrench, spark plug socket
• Remove the ignition coil from cylinder 1.
  • Disconnect the electrical connector.
  • Remove the mounting bolts and lift the coil out.
• Remove the spark plug using a spark plug socket.
• Inspect the spark plug for wear (evidence of fouling, excessive gap, or damage).
• Replace with a new spark plug (specifications: NGK or Denso brand, gap per manufacturer specs).
• Torque the spark plug to the manufacturer's specification (typically around 13-15 ft-lbs).
• Reinstall the ignition coil.

3. Inspect and Replace Ignition Coil (if necessary)

• If the spark plug was in good condition, proceed to check the ignition coil.
• Tools Required: Multimeter
• Test the ignition coil for resistance using a multimeter (primary and secondary resistance).
• If the ignition coil is faulty, replace it with a new OEM coil.
• Reconnect the ignition coil and electrical connector after replacement.

4. Check Fuel Injector

• If misfire persists, inspect the fuel injector for cylinder 1.
• Tools Required: Fuel pressure gauge, injector cleaning kit
• Perform a fuel pressure test to ensure proper fuel delivery.
• If the injector is clogged or malfunctioning, clean or replace it as necessary.

5. Reassemble and Reconnect

• Reconnect the negative battery terminal.
• Ensure all connectors and bolts are secured.