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

Solution

1. Preparation

• Gather the necessary tools and parts.
• Disconnect the battery to ensure safety.
• Allow the engine to cool completely before starting work.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, torque wrench.
• Instructions:
  1. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
  2. Disconnect the electrical connectors from both sensors.
  3. Use the O2 sensor socket to remove the upstream oxygen sensor.
  4. Install the new upstream oxygen sensor and torque to manufacturer's specification (typically around 30 lb-ft).
  5. Repeat the process for the downstream oxygen sensor if necessary.

3. Inspect and Replace Catalytic Converter

• Tools Required: Socket set, torque wrench, exhaust hanger removal tool.
• Instructions:
  1. Raise the vehicle and securely support it with jack stands.
  2. Remove any exhaust hangers securing the catalytic converter using the exhaust hanger removal tool.
  3. Unbolt the catalytic converter from the exhaust manifold and the exhaust pipe.
  4. Inspect the catalytic converter for signs of damage or blockage. Replace if necessary.
  5. Install the new catalytic converter, ensuring proper alignment and torque all bolts to manufacturer specifications.

4. Clear Codes and Test Drive

• Tools Required: OBD-II scanner.
• Instructions:
  1. Reconnect the battery.
  2. Use the OBD-II scanner to clear the P0420 code from the engine control unit (ECU).
  3. Start the engine and let it idle for a few minutes.
  4. Take the vehicle for a test drive to ensure the issue is resolved and check for reoccurrence of the code.