how to fix the P0420 code in my Toyota RAV4 Fifth Generation (2019-present)

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the battery to ensure safety during inspection and repairs.
• Allow the exhaust system to cool before working on it.

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  1. Locate the upstream (pre-catalytic converter) and downstream (post-catalytic converter) oxygen sensors.
  2. Using the appropriate socket, carefully unscrew and remove the faulty oxygen sensor(s).
  3. Inspect the connectors for corrosion or damage.
  4. Install the new oxygen sensor(s) by reversing the removal process; ensure they are properly tightened (typically 30-40 ft-lbs).
  5. Reconnect the battery.

3. Examine and Replace Catalytic Converter (if necessary)

• Sub-steps:
  1. If the oxygen sensors are operational, inspect the catalytic converter for any signs of damage or blockage.
  2. Remove any heat shields or brackets securing the catalytic converter.
  3. Use a wrench to unbolt the catalytic converter from the exhaust system.
  4. Install the new catalytic converter, ensuring that all bolts are torqued to the manufacturer's specifications (typically 30-40 ft-lbs).
  5. Reattach any heat shields or brackets.

4. Test for Exhaust Leaks

• Sub-steps:
  1. Start the engine and allow it to reach normal operating temperature.
  2. Inspect the exhaust system visually and audibly for any leaks.
  3. If leaks are found, repair or replace the affected components as needed.