how to fix P0301 code in Toyota Highlander Fourth Generation (2020-present)

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the battery to ensure safety while working on electrical components.

Tools Required:

• OBD-II scanner
• Spark plug socket
• Torque wrench
• Compression tester
• Multimeter
• Basic socket set
• Screwdrivers

2. Replace Spark Plug

1. Remove Engine Cover (if applicable)
   • Use a socket or screwdriver to remove any screws or bolts holding the cover.
2. Remove Spark Plug
   • Use a spark plug socket to carefully unscrew and remove the spark plug from cylinder 1.
3. Install New Spark Plug
   • Check the gap of the new spark plug and adjust if necessary.
   • Apply a small amount of anti-seize compound on the threads.
   • Hand-tighten the new spark plug, then torque it to the manufacturer’s specifications (typically around 13-16 ft-lbs).

3. Replace Ignition Coil

1. Disconnect Wiring Harness
   • Carefully pull off the connector from the ignition coil.
2. Remove Ignition Coil
   • Unscrew the bolts holding the ignition coil in place and lift it out.
3. Install New Ignition Coil
   • Position the new ignition coil and secure it with bolts.
   • Reconnect the wiring harness.

4. Inspect and Test Fuel Injector

1. Remove Fuel Injector Connector
   • Carefully disconnect the fuel injector connector from cylinder 1.
2. Test Fuel Injector
   • Use a multimeter to check for continuity and proper voltage at the connector.
3. Replace Fuel Injector (if required)
   • If the injector is faulty, remove the retaining clips and pull out the injector.
   • Install the new injector, ensuring to lubricate the O-rings before installation, then reconnect the connector.

5. Final Steps

• Reconnect the battery.
• Clear the P0301 code using the OBD-II scanner.
• Start the engine and monitor for any misfire symptoms.