how to fix P0301 misfire code on my Toyota Corolla E170 (2013-2019)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool down before working on it.

2. Replace Spark Plug

• Tools Required: Spark plug socket, ratchet, torque wrench, dielectric grease
• Remove the ignition coil by unscrewing the mounting bolt and disconnecting the electrical connector.
• Remove the spark plug using the spark plug socket.
• Inspect the spark plug for signs of wear or fouling.
• Install a new spark plug, applying dielectric grease to the threads.
• Torque the spark plug to the manufacturer’s specifications (typically around 13-15 ft-lbs).

3. Inspect and Replace Ignition Coil

• Tools Required: Ratchet and socket set
• Check the ignition coil for any visible damage or cracks.
• Swap the ignition coil from cylinder 1 with another cylinder to see if the misfire follows the coil.
• If the misfire does follow, replace the ignition coil with a new one.
• Reinstall the ignition coil onto cylinder 1 and reconnect the electrical connector.

4. Inspect Fuel Injector

• Tools Required: Fuel injector tester or multimeter
• Test the fuel injector for cylinder 1 to ensure it is receiving the proper voltage and is functioning correctly.
• If the injector is faulty, replace it with a new one.
• Make sure to clean any debris from the injector port before installation.

5. Perform Compression Test

• Tools Required: Compression tester
• Remove all spark plugs for easier access.
• Insert the compression tester into the spark plug hole of cylinder 1.
• Crank the engine and record the pressure reading.
• Compare the reading to the manufacturer’s specifications (typically around 180-200 psi).
• If compression is low, further investigation into engine internals may be necessary.