how to fix the 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.
• Allow the engine to cool before starting work.

2. Inspect and Replace Oxygen Sensors (if necessary)

• Tools Required: O2 sensor socket, wrench set, torque wrench.
• Sub-steps:
  1. Locate the upstream (pre-cat) and downstream (post-cat) oxygen sensors.
  2. Disconnect the electrical connectors from both sensors.
  3. Use the O2 sensor socket to remove the sensors from the exhaust pipe.
  4. Install the new oxygen sensors by screwing them in by hand, then tightening to the manufacturer’s specifications (typically around 30 lb-ft).
  5. Reconnect the electrical connectors securely.

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, jack and jack stands, exhaust hanger removal tool.
• Sub-steps:
  1. Raise the vehicle securely using jack stands.
  2. Remove the exhaust pipe bolts connecting to the catalytic converter.
  3. Use the exhaust hanger removal tool to detach the exhaust hangers from the catalytic converter.
  4. Remove the old catalytic converter from the vehicle.
  5. Install the new catalytic converter, ensuring proper alignment.
  6. Reattach the exhaust pipe and tighten the bolts to the recommended torque (usually around 30-40 lb-ft).

4. Clear Error Codes

• Use the OBD-II scanner to clear the P0420 code from the vehicle's computer.
• Reconnect the negative battery terminal.