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

Solution

1. Preparation

• Gather tools and parts needed.
• Disconnect the battery to ensure safety.
• Allow the engine to cool down before starting work.

2. Inspect and Replace Spark Plug

• Tools Required: Socket set, torque wrench, spark plug socket.
• Remove the ignition coil on Cylinder 1 by unbolting it and disconnecting the electrical connector.
• Remove the spark plug using the spark plug socket.
• Inspect the spark plug for signs of wear or deposits. Replace if necessary.
• Install the new spark plug and torque it to the manufacturer’s specifications (typically around 13-15 lb-ft).
• Reattach the ignition coil and reconnect the electrical connector.

3. Check and Replace Ignition Coil

• Tools Required: Torque wrench, socket set.
• If the ignition coil appears defective, remove it from Cylinder 1.
• Test the ignition coil with a multimeter to ensure it is functioning within specifications.
• Replace the ignition coil if it is faulty.
• Reinstall the new or tested ignition coil and torque it to manufacturer specifications.

4. Inspect and Test Fuel Injector

• Tools Required: Fuel pressure gauge, multimeter.
• Disconnect the fuel injector connector for Cylinder 1.
• Use a multimeter to check for proper voltage at the connector while cranking the engine.
• Remove the fuel injector and visually inspect it for clogs or damage.
• Test the injector with a fuel pressure gauge to ensure it is delivering fuel correctly.
• Replace the fuel injector if malfunctioning.

5. Compression Test

• Tools Required: Compression tester.
• Remove all spark plugs for easier cranking.
• Insert the compression tester into Cylinder 1 and crank the engine.
• Record the compression reading and compare it to manufacturer specifications (typically 160-200 psi).
• If the compression is low, further investigation is needed for possible internal engine issues.

6. Check for Vacuum Leaks

• Inspect all vacuum hoses and connections around the intake manifold for cracks or disconnections.
• Use a smoke machine or carburetor cleaner to detect any vacuum leaks.
• Repair any leaks found to ensure proper air-fuel mixture.