how to address P0420 code in my Toyota Corolla E210 (2019-2024) exhaust system

Solution

1. Preparation

• Gather all required tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the negative battery terminal to avoid electrical shocks.

2. Inspect and Replace Oxygen Sensors

1. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
2. Using a socket wrench, carefully remove the oxygen sensors.
3. Inspect the threads for damage and the connectors for corrosion.
4. Replace with new oxygen sensors if faulty; ensure they match OEM specifications.
5. Reconnect the sensors securely.

3. Inspect and Clean or Replace Catalytic Converter

1. If the catalytic converter is suspected of being clogged, remove it from the exhaust system.
   • Use a pipe cutter or saw if necessary to cut exhaust pipes.
2. Inspect the catalytic converter for physical damage or blockage.
3. If cleaning is needed, use a catalytic converter cleaner and follow the instructions.
4. If damaged, replace the catalytic converter with a new OEM or quality aftermarket part.
5. Reinstall the catalytic converter and ensure all connections are secure.

4. Reconnect Battery and Clear Codes

1. Reconnect the negative battery terminal.
2. Use the OBD-II scanner to clear the P0420 code from the vehicle's computer.
3. Start the engine and let it reach operating temperature.