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

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the battery to prevent any electrical issues during the repair.
• Allow the engine to cool down before proceeding with work.

2. Inspect and Replace Oxygen Sensors

1. Remove the upstream oxygen sensor:
   • Use an oxygen sensor socket to unscrew the sensor from the exhaust manifold.
   • Ensure the connector is disconnected before removal.
2. Replace with a new oxygen sensor:
   • Install the new sensor and tighten to manufacturer's specifications (typically around 30 lb-ft).
   • Reconnect the electrical connector.
3. Repeat for the downstream oxygen sensor if necessary.

3. Inspect and Replace the Catalytic Converter

1. Remove the catalytic converter:
   • Safely lift the vehicle and support it with jack stands.
   • Disconnect the exhaust pipes connected to the catalytic converter using a socket set.
   • Remove any mounting brackets or bolts securing the catalytic converter.
2. Inspect the catalytic converter for damage or blockage:
   • Look for signs of physical damage, overheating, or rattling.
3. Install the new catalytic converter:
   • Position the new catalytic converter in place and secure it using the original bolts or new ones as required.
   • Tighten to the proper torque specifications.
4. Reconnect exhaust pipes and any brackets.

4. Clear Codes and Test

1. Reconnect the battery.
2. Clear the check engine light using the OBD-II scanner.
3. Perform a test drive to ensure the code does not return.