how to fix P0420 code on my Toyota Highlander XU70 (2020-Present)

Solution

1. Preparation

• Gather necessary tools and parts.
• Gather a multimeter, OBD-II scanner, jack stands, and safety goggles.
• Disconnect the battery to ensure safety.

2. Inspect and Replace Oxygen Sensors (if necessary)

• Sub-steps:
  • Locate the upstream and downstream oxygen sensors.
  • Use an O2 sensor socket to remove the sensors.
  • Inspect the sensors for any signs of wear or contamination.
  • Install the new sensors by threading them into place and tightening to the manufacturer's specification (usually around 30 lb-ft).
  • Reconnect the electrical connectors.

3. Inspect and Replace the Catalytic Converter (if necessary)

• Sub-steps:
  • Raise the vehicle and secure it with jack stands.
  • Disconnect any exhaust hangers or brackets securing the catalytic converter.
  • Remove the bolts connecting the catalytic converter to the exhaust system using a socket set.
  • Inspect the old catalytic converter for damage or clogs.
  • Install the new catalytic converter, ensuring proper alignment and sealing.
  • Tighten the bolts to the manufacturer's specified torque (usually around 30-40 lb-ft).
  • Reattach hangers and brackets as necessary.

4. Clear the Codes

• Reconnect the battery and use the OBD-II scanner to clear the P0420 code.
• Start the engine and allow it to reach operating temperature.