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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the vehicle battery to ensure safety.
• Allow the engine to cool completely.

2. Inspect and Replace Oxygen Sensors

1. Locate the upstream and downstream oxygen sensors.
2. Using an O2 sensor socket, carefully remove the defective upstream O2 sensor.
3. Install the new upstream O2 sensor and torque it to the manufacturer's specification (usually around 30 lb-ft).
4. Repeat the process for the downstream O2 sensor if it was also found defective.

3. Inspect and Replace the Catalytic Converter

1. If the catalytic converter is determined to be faulty, locate the mounting bolts securing the catalytic converter to the exhaust system.
2. Using a socket set, remove the bolts and disconnect the exhaust pipes from the catalytic converter.
3. Remove the old catalytic converter and inspect the gaskets; replace if necessary.
4. Install the new catalytic converter, ensuring it aligns properly with the exhaust system.
5. Torque the mounting bolts to the manufacturer's specifications (usually around 40 lb-ft).

4. Clear the Codes

1. Reconnect the vehicle battery.
2. Use the OBD-II scanner to clear the P0420 code from the vehicle's computer.
3. Start the vehicle and allow it to run until it reaches operating temperature.