how to diagnose P0301 code on Toyota Corolla E170 (2013-2019)

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Tools Required: OBD-II scanner, socket set, torque wrench, multimeter, compression tester, noid light.
• Safety Warnings: Disconnect the negative battery terminal before starting any electrical work.

2. Replace Spark Plug

• Remove the engine cover if applicable.
• Disconnect the ignition coil from cylinder 1.
• Remove the spark plug using a spark plug socket and ratchet.
• Inspect the spark plug for excessive wear, fouling, or damage.
• Install a new spark plug with the correct gap (usually 0.043 inches for many Corollas).
• Torque the spark plug to the manufacturer's specification (typically around 13 lb-ft).
• Reconnect the ignition coil.

3. Replace Ignition Coil (if needed)

• If the ignition coil was faulty as determined in diagnostic steps, remove it from cylinder 1.
• Install the new ignition coil and reconnect the electrical connector.
• Ensure it is seated properly and secure any mounting bolts.

4. Clean or Replace Fuel Injector (if needed)

• If the fuel injector is not functioning correctly, remove the fuel rail and disconnect the fuel injector connector.
• Remove the fuel injector from cylinder 1.
• Clean the injector using an ultrasonic cleaner or replace it with a new one.
• Reinstall the fuel injector and reconnect the fuel rail and connectors.

5. Reassemble and Reconnect

• Reinstall any components removed during the repair, ensuring all connections are secure.
• Reconnect the negative battery terminal.