how to resolve the P0302 misfire code in my Toyota Corolla E170 (2013-2019)

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Ensure the engine is cool before starting work.

2. Inspect and Replace Spark Plug

• Tools Required: Socket set, torque wrench, spark plug socket, dielectric grease.
• Remove the ignition coil by unscrewing the retaining bolts and carefully pulling it out.
• Remove the spark plug using a spark plug socket. Inspect the spark plug for wear and carbon buildup.
• If worn, replace the spark plug with a new one, ensuring it is gapped correctly according to specifications (typically around 0.043 inches).
• Apply dielectric grease to the boot of the ignition coil before reinstallation.

3. Check and Replace Ignition Coil (if necessary)

• If the spark plug is in good condition but the misfire persists, inspect the ignition coil.
• Swap the ignition coil with another cylinder (e.g., cylinder 1) to see if the misfire code follows the coil.
• If the misfire code moves to the other cylinder, replace the faulty ignition coil.

4. Inspect and Clean Fuel Injector

• Tools Required: Fuel injector cleaner, basic hand tools.
• Disconnect the fuel line from the fuel injector cautiously to prevent fuel spillage.
• Remove the fuel injector from cylinder 2.
• Clean the injector using a fuel injector cleaning kit or replace it if it’s clogged or malfunctioning.
• Reinstall the injector and reconnect the fuel line.

5. Perform Compression Test

• Tools Required: Compression tester.
• Remove the spark plug from cylinder 2 and connect the compression tester.
• Crank the engine and record the compression reading; compare it with specifications (usually around 180-200 psi).
• If compression is low, further investigation into potential internal engine problems is needed.