how to fix P0420 code on Toyota Corolla E140 (2006-2013)

Solution

1. Preparation

• Gather tools and parts needed for repair.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  1. Locate the upstream (pre-catalytic converter) and downstream (post-catalytic converter) oxygen sensors.
  2. Use a socket wrench to unscrew the sensors from their respective locations.
  3. Inspect the connectors and wiring for damage or corrosion.
  4. Install new oxygen sensors, ensuring they are securely tightened (torque to manufacturer specifications).
  5. Reconnect the battery terminal.

3. Inspect and Replace Catalytic Converter

• Sub-steps:
  1. Safely lift the vehicle and support it with jack stands.
  2. Remove any heat shields covering the catalytic converter.
  3. Disconnect the exhaust pipes from both ends of the catalytic converter using a socket set.
  4. Remove the old catalytic converter and inspect the gaskets for damage. Replace if necessary.
  5. Install the new catalytic converter, ensuring all connections are sealed and torqued to specifications.
  6. Reinstall heat shields if applicable.

4. Clear the Codes

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