how to diagnose P0302 misfire code in Toyota Corolla E140 (2006-2013)

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Spark Plug

• Tools Required: Socket set, torque wrench, spark plug socket.
• Remove the ignition coil cover (if applicable) and the ignition coil from cylinder 2.
• Remove the spark plug from cylinder 2 using a spark plug socket.
• Inspect the spark plug for wear or damage; replace if necessary (OEM specifications recommend replacing spark plugs every 30,000 miles).
• Install the new spark plug and torque it to the manufacturer's specification (typically around 13 lb-ft).
• Reinstall the ignition coil.

3. Test and Replace Fuel Injector (if needed)

• Tools Required: Fuel injector tester or multimeter, fuel line removal tool.
• Disconnect the fuel injector connector for cylinder 2.
• Use a fuel injector tester to check for proper operation; if the injector fails to operate, replace it.
• Install a new fuel injector, ensuring it is properly seated and connected.

4. Compression Test

• Tools Required: Compression gauge.
• Remove the spark plug from cylinder 2.
• Insert the compression gauge into the spark plug hole and crank the engine for several revolutions.
• Record the compression reading; compare it to manufacturer specifications (typically around 180 psi).
• If the compression is low, further investigation into mechanical issues is necessary.

5. Check for Vacuum Leaks

• Tools Required: Smoke machine or carb cleaner.
• Visually inspect hoses and gasket seals for cracks or damage.
• Use a smoke machine to detect leaks or spray carb cleaner around the intake area while the engine is running to observe idle changes.
• Repair or replace any defective components found.