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

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the negative terminal of the battery to ensure safety during repairs.

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  • Locate the upstream (pre-catalytic converter) and downstream (post-catalytic converter) oxygen sensors.
  • Remove the connectors from both sensors.
  • Unscrew the sensors using an O2 sensor socket.
  • Install the new oxygen sensors, ensuring they are tightened to manufacturer specifications (typically around 30-40 ft-lbs).
  • Reconnect the electrical connectors.

3. Inspect and Replace Catalytic Converter (if necessary)

• Sub-steps:
  • Raise the vehicle using a jack and secure with jack stands.
  • Remove the exhaust pipe connected to the catalytic converter, using a socket set to unbolt it.
  • Inspect the catalytic converter for signs of damage or clogging.
  • If replacement is needed, install the new catalytic converter, ensuring proper alignment and secure bolting (torque to manufacturer specifications, usually around 30-40 ft-lbs).
  • Reinstall the exhaust pipe and ensure all connections are sealed properly.

4. Reset the OBD-II System

• Sub-steps:
  • Reconnect the negative battery terminal.
  • Use an OBD-II scanner to clear the P0420 code from the system.
  • Start the engine and let it idle for a few minutes to ensure the system is functioning correctly.