how to address P0301 misfire code in Toyota Corolla E140 (2006-2013)?

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the negative terminal of the battery to prevent electrical shorts.
• Allow the engine to cool before starting work.

2. Inspect and Replace Spark Plug

• Tools Required: Socket set, torque wrench, gap gauge.
• Remove the ignition coil on cylinder 1 by unbolting it.
• Remove the spark plug using a socket and ratchet.
• Inspect the spark plug for wear or damage; replace it if necessary.
• Ensure the new spark plug is gapped correctly according to manufacturer specifications (typically 0.044 inches for Corolla).
• Reinstall the spark plug and torque it to the manufacturer’s specification (usually around 13 lb-ft).
• Reattach the ignition coil.

3. Check and Replace Ignition Coil (if necessary)

• If the spark plug is in good condition, test the ignition coil.
• Use a multimeter to check the primary and secondary resistance of the ignition coil.
• If the coil is faulty, replace it with a new one.
• Reinstall the ignition coil after replacing it.

4. Inspect and Replace Fuel Injector (if necessary)

• If the ignition system is functioning properly, check the fuel injector for cylinder 1.
• Remove the fuel rail and injector for inspection.
• Test the injector for proper operation using a noid light or by measuring resistance.
• Replace the fuel injector if it is found to be defective.
• Reassemble the fuel rail and reconnect all lines and connectors.

5. Perform a Compression Test (if misfire persists)

• Remove the spark plug from cylinder 1 and install a compression gauge.
• Crank the engine and record the compression reading.
• Compare the reading to specifications (typically around 180 psi for a healthy engine).
• If compression is low, further investigation is needed for internal engine repairs.