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

Solution

1. Preparation

• Gather the necessary tools and parts.
• Disconnect the battery to prevent electrical shorts.
• Allow the engine to cool before beginning work.

2. Inspect and Replace Spark Plug

• Tools Required: Socket set, torque wrench, dielectric grease
• Remove the engine cover if applicable.
• Disconnect the ignition coil connector and remove the ignition coil from cylinder 1.
• Remove the spark plug using a spark plug socket.
• Inspect the spark plug for wear or carbon buildup; replace if necessary.
• Apply dielectric grease to the new spark plug's threads and install it, tightening to manufacturer specifications (typically 13-15 lb-ft).
• Reinstall the ignition coil and reconnect the electrical connector.

3. Check and Replace Ignition Coil

• If the spark plug is fine, inspect the ignition coil for cracks or damage.
• Tools Required: Socket set
• Remove the ignition coil from cylinder 1.
• If defective, replace the ignition coil with a new part and ensure it is seated properly.
• Reconnect the ignition coil connector.

4. Inspect and Clean Fuel Injector

• If misfire persists, check the fuel injector for cylinder 1.
• Tools Required: Fuel injector cleaning kit (if cleaning), socket set
• Disconnect the fuel injector connector and remove the injector.
• Clean the injector using a fuel injector cleaning kit or replace it if it’s faulty.
• Reinstall the injector and reconnect the electrical connector.

5. Verify Engine Health

• If the issue is still unresolved, perform a compression test on cylinder 1.
• If compression is low, further engine diagnosis may be required (e.g., valve issues or head gasket failure).