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

Solution

1. Preparation

• Gather all necessary tools and components.
• Disconnect the vehicle's battery to ensure safety.
• Ensure the engine is cool before beginning work.

2. Inspect and Replace Spark Plug

• Remove the ignition coil cover if necessary.
• Disconnect the electrical connector from the ignition coil on cylinder 1.
• Remove the ignition coil using a socket set.
• Inspect the spark plug using a spark plug socket; replace it if worn or damaged.
• Install the new spark plug, ensuring it’s properly gapped according to manufacturer specifications (0.044 inches for most Toyota engines).
• Reinstall the ignition coil and reconnect the electrical connector.

3. Check and Replace Ignition Coil (if needed)

• If the ignition coil was suspected to be faulty, test it by swapping it with another cylinder's coil.
• If the misfire moves to the new cylinder, replace the ignition coil with a new one that meets OEM specifications.
• Reconnect the ignition coil and ensure it is securely fastened.

4. Test and Clean Fuel Injector

• If the fuel injector is suspected, remove it from cylinder 1.
• Clean the injector using a professional fuel injector cleaning kit or replace it if necessary.
• Reinstall the injector and ensure all seals are in good condition.

5. Perform Compression Test

• Remove the spark plug and insert the compression gauge into cylinder 1.
• Crank the engine and record the compression reading; it should be within the manufacturer’s specified range.
• If the reading is low, further investigation into valve seals or piston rings is required.