how to fix P0301 misfire code on Toyota Corolla E210 (2019-2024)

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, torque wrench, multimeter, compression tester, basic hand tools.
• Safety Warnings: Disconnect the battery before working on the ignition system. Allow the engine to cool before opening the hood.

2. Replace Spark Plug

• Remove the engine cover if applicable.
• Disconnect the ignition coil connector.
• Remove the bolt securing the ignition coil and gently pull it out.
• Remove the old spark plug using a spark plug socket and ratchet.
• Inspect the old spark plug for wear; if it appears worn, replace it.
• Install a new spark plug using a torque wrench set to the manufacturer's specification (typically around 13-19 lb-ft).
• Reinstall the ignition coil and reconnect the connector.

3. Replace Ignition Coil

• If the spark plug replacement did not resolve the issue, proceed to replace the ignition coil.
• Remove the ignition coil as described in the previous step.
• Compare the old ignition coil to the new one for compatibility.
• Install the new ignition coil, securing it with the bolt and reconnecting the harness.

4. Test Fuel Injector

• If misfire persists, test the fuel injector for cylinder 1.
• Disconnect the fuel injector connector.
• Use a noid light to check for signal. If no signal, inspect wiring.
• If the signal is present, use a multimeter to check resistance (should typically be between 12-16 ohms).
• Replace the fuel injector if it is faulty.

5. Perform Compression Test

• If all components check out, perform a compression test on cylinder 1.
• Remove the spark plug and thread in the compression tester.
• Crank the engine and note the reading; it should generally be within the manufacturer’s specified range (check service manual).
• If compression is low, further investigation into engine internals may be necessary.