how to fix P0420 code in Toyota Corolla E170 (2013-2019)

Solution

1. Preparation

• Gather all tools and parts needed for the repair.
• Safety gear: gloves, safety glasses, and appropriate clothing.
• Ensure the vehicle is parked on a flat surface and the engine is cool.

2. Inspect Exhaust System

• Tools Required: Socket set, jack and jack stands.
• Raise the vehicle using a jack and secure it with jack stands.
• Inspect the exhaust system for any visible cracks, holes, or loose connections.
• Tighten any loose bolts and replace gaskets if needed.

3. Check Oxygen Sensors

• Tools Required: O2 sensor socket, multimeter.
• Disconnect the electrical connectors from the upstream and downstream oxygen sensors.
• Use the O2 sensor socket to remove both sensors from the exhaust system.
• Inspect the sensor tips for contamination or damage and replace if necessary.

4. Replace Catalytic Converter (if needed)

• Tools Required: Cutting torch or saw (if necessary), socket set.
• If the catalytic converter is damaged, remove it from the exhaust pipe by cutting or unbolting it.
• Install the new catalytic converter, ensuring that all gaskets are replaced, and torque the bolts to the manufacturer's specifications.

5. Reinstall Oxygen Sensors

• Reinstall the upstream and downstream oxygen sensors and reconnect their electrical connectors.
• Ensure that they are tightened to the manufacturer's specifications.

6. Clear Codes and Test Drive

• Use the OBD-II scanner to clear the P0420 code.
• Start the engine and allow it to idle for a few minutes.
• Take the vehicle for a test drive to ensure the check engine light does not reappear.