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

Solution

1. Preparation

• Gather required tools and parts.
• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the battery to prevent electrical shock.

2. Inspect and Replace Oxygen Sensors

1. Locate the Oxygen Sensors:
   • Identify the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors on the exhaust manifold and exhaust pipe, respectively.
2. Remove the Oxygen Sensors:
   • Use an oxygen sensor socket to unscrew the sensors from their locations.
   • Check the wiring for any damage or corrosion.
3. Install New Oxygen Sensors:
   • Apply anti-seize compound on the threads of the new sensors (if applicable).
   • Thread the sensors into place and tighten them to the manufacturer's specifications (usually around 30 Nm).
4. Reconnect Battery:
   • Reconnect the negative battery terminal.

3. Inspect and Replace Catalytic Converter

1. Remove the Old Catalytic Converter:
   • Loosen the exhaust clamps and bolts securing the catalytic converter.
   • Carefully detach the converter from the exhaust system.
2. Install New Catalytic Converter:
   • Position the new catalytic converter and secure it with the original bolts and clamps.
   • Ensure all connections are tight and free of leaks.
3. Recheck Exhaust System:
   • Inspect the entire exhaust system for any leaks or loose connections.

4. Clear Codes and Test Drive

1. Clear the OBD-II Codes:
   • Use the OBD-II scanner to erase the P0420 code from the vehicle’s computer.
2. Test Drive the Vehicle:
   • Drive the vehicle for a minimum of 20 minutes under various driving conditions to allow the system to monitor the catalytic converter’s performance.