how to fix P0420 code in Toyota Corolla E210 (2019-2024)?

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to ensure safety.
• Allow the vehicle to cool down before starting work.

2. Inspect and Replace Oxygen Sensors

1. Locate the oxygen sensors: Identify the upstream (pre-catalytic converter) and downstream (post-catalytic converter) sensors.
2. Disconnect the sensors: Unplug the electrical connectors from both oxygen sensors.
3. Remove the sensors: Use an oxygen sensor socket to carefully unscrew and remove the sensors from the exhaust system.
4. Install new sensors: Apply anti-seize compound to the threads of the new sensors and install them, tightening to manufacturer's torque specifications (typically around 30 lb-ft).
5. Reconnect the electrical connectors: Ensure all connections are secure.

3. Inspect and Replace the Catalytic Converter (if necessary)

1. Remove the exhaust components: If no issues found with the sensors, support the exhaust system and remove bolts securing the catalytic converter.
2. Inspect the catalytic converter: Check for any physical damage, clogs, or excessive carbon buildup.
3. Install new catalytic converter: Position the new catalytic converter and secure it with bolts to the exhaust manifold and exhaust pipe. Torque to manufacturer specifications (typically around 30-40 lb-ft).
4. Reassemble exhaust components: Ensure all components are properly aligned and secured.

4. Reset the Engine Control Module (ECM)

1. Reconnect the battery: Reattach the negative battery terminal.
2. Clear the trouble codes: Use an OBD-II scanner to clear the P0420 code from the ECM.
3. Drive cycle: Perform a drive cycle to allow the vehicle to recheck the catalytic converter efficiency.