how to fix P0301 cylinder 1 misfire code on Toyota Corolla E210 (2019-2024)

Solution

1. Preparation

• Gather all tools and parts needed.
• Disconnect the negative battery terminal to prevent electrical shock.
• Allow the engine to cool down before starting work.

2. Replace Spark Plug

• Remove the ignition coil from cylinder 1 by unscrewing the mounting bolt and disconnecting the electrical connector.
• Remove the spark plug using a socket wrench.
• Inspect the old spark plug for wear; if necessary, replace it with a new one.
• Torque the new spark plug to the manufacturer’s specifications (typically around 13-15 ft-lbs).

3. Replace Ignition Coil (if faulty)

• If the ignition coil appears damaged or if the spark plug was not the issue, replace the ignition coil.
• Install the new ignition coil by reversing the removal process; ensure it is seated properly.
• Reconnect the electrical connector and secure it with the mounting bolt.

4. Check Fuel Injector Operation

• If the issue persists, test the fuel injector for cylinder 1.
• Disconnect the fuel injector connector, then use a noid light to verify injector pulse.
• If no pulse is detected, check for wiring issues; if pulse is present, consider replacing the fuel injector.

5. Perform Compression Test

• If misfire continues, perform a compression test on cylinder 1.
• Remove the spark plug and screw in the compression tester.
• Crank the engine and record the compression reading; it should be within the manufacturer’s specified range (generally around 180-200 psi).
• If compression is low, further investigation into valve or piston issues will be needed.