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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to ensure safety.
• Allow the engine to cool completely before starting work.

2. Inspect and Replace Spark Plug

• Tools Required: Socket set, torque wrench, spark plug socket, dielectric grease.
• Remove the ignition coil from cylinder 1.
• Extract the spark plug using a spark plug socket.
• Inspect the spark plug for signs of wear or fouling.
• If necessary, replace the spark plug with a new one, ensuring to apply dielectric grease on the threads.
• Torque the new spark plug to the manufacturer's specified torque (typically around 13-15 lb-ft).

3. Inspect and Replace Ignition Coil

• Tools Required: Socket set.
• Remove the ignition coil for cylinder 1 if the spark plug replacement did not resolve the issue.
• Inspect the ignition coil for cracks or damage.
• If damaged, replace the ignition coil with a new one.
• Reinstall the ignition coil and ensure it is properly seated.

4. Check and Test Fuel Injector

• Tools Required: Noid light or multimeter.
• Disconnect the fuel injector connector for cylinder 1.
• Use a noid light to check if the fuel injector is receiving a signal. If using a multimeter, measure resistance (should be within manufacturer specs).
• If not functioning, replace the fuel injector with a new one.
• Reconnect the fuel injector harness.

5. Perform Compression Test

• Tools Required: Compression gauge.
• Remove the spark plug from cylinder 1.
• Insert the compression gauge into the spark plug hole.
• Crank the engine several times to obtain a reading.
• Compare the reading to the manufacturer's specifications (usually between 150-200 psi). If compression is low, further engine diagnostics may be required.