how to fix P0420 code on my Toyota Corolla E210 (2019-2024)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to ensure safety.

2. Inspect and Replace Oxygen Sensors

1. Locate the oxygen sensors: Identify the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
2. Remove old sensors: Use an oxygen sensor socket or wrench to carefully unscrew the sensors from the exhaust system.
3. Install new sensors: Apply anti-seize compound to the threads of the new sensors, then screw them into place and tighten to manufacturer specifications (typically about 30-40 ft-lbs).
4. Reconnect electrical connectors: Ensure all wiring harnesses are securely connected.

3. Inspect and Replace Catalytic Converter (if necessary)

1. Raise the vehicle: Use jack stands to safely lift the vehicle.
2. Remove exhaust components: Unbolt the catalytic converter from the exhaust manifold and the mid-pipe, using a socket set.
3. Inspect the old catalytic converter: Check for signs of damage or clogging.
4. Install a new catalytic converter: Position the new converter in place, and tighten the bolts to the specified torque (typically around 20-25 ft-lbs).
5. Reattach any exhaust components: Ensure all connections are tight and secure.

4. Clear Codes and Test

1. Reconnect battery: Connect the negative battery terminal.
2. Clear the stored error codes: Use an OBD-II scanner to erase the P0420 code.
3. Test drive the vehicle: Monitor performance over a 20-30 minute drive under various conditions.