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

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the negative battery terminal to avoid electrical shorts.

2. Replace Spark Plug

1. Remove the engine cover if necessary to access the ignition coil and spark plug.
2. Disconnect the ignition coil connector for cylinder 1.
3. Unbolt and remove the ignition coil from cylinder 1.
4. Remove the spark plug using a spark plug socket and ratchet.
5. Inspect the old spark plug and ensure the gap is set to the manufacturer's specifications (typically around 0.044 inches for Toyota).
6. Install the new spark plug, tightening it to the manufacturer’s specified torque value (typically 13 lb-ft).
7. Reinstall the ignition coil, ensuring it is seated properly and reconnect the electrical connector.

3. Replace Ignition Coil (if necessary)

1. If the ignition coil was found to be faulty during diagnostics, proceed to replace it.
2. Remove the faulty ignition coil as detailed in the previous step.
3. Install the new ignition coil, ensuring it clicks into place.
4. Reconnect the electrical connector to the ignition coil.

4. Inspect Fuel Injector

1. If the spark plug and ignition coil are functioning correctly, verify the fuel injector operation.
2. Disconnect the fuel injector connector for cylinder 1.
3. Perform a resistance test on the fuel injector with a multimeter; it should be within the manufacturer's specified range (typically around 12-16 ohms).
4. If the injector is faulty, replace it by removing the fuel rail if needed and installing a new injector.