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

Solution

1. Preparation

• Gather all necessary tools and parts.
• Park the vehicle on a level surface, engage the parking brake, and ensure the engine is off and cool.
• Disconnect the negative battery terminal to ensure safety while working on electrical components.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench
• If the pre-catalytic converter O2 sensor is faulty:
  1. Locate the O2 sensor before the catalytic converter (usually near the exhaust manifold).
  2. Unplug the electrical connector from the sensor.
  3. Use the O2 sensor socket to remove the sensor from the exhaust pipe.
  4. Install the new O2 sensor by threading it into the exhaust pipe and tightening it to the manufacturer's torque specification (typically 30 ft-lbs).
  5. Reconnect the electrical connector.

3. Replace the Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, exhaust hanger removal tool, gasket scraper
• If the catalytic converter is found to be defective:
  1. Support the vehicle on jack stands and remove the underbody shield if applicable.
  2. Unbolt the catalytic converter from the exhaust system using the socket set.
  3. Remove any exhaust hangers using the exhaust hanger removal tool.
  4. Clean the mating surfaces of the exhaust pipe and manifold to remove old gasket material.
  5. Install the new catalytic converter, ensuring proper alignment.
  6. Secure it with bolts and tighten to the manufacturer's torque specifications (usually around 30-40 ft-lbs).
  7. Reinstall any exhaust hangers and underbody shields.

4. Clear Error Codes

• Reconnect the negative battery terminal.
• Use the OBD-II scanner to clear the P0420 code and any other stored codes.

5. Test Drive

• Start the vehicle and allow it to reach operating temperature.
• Take the vehicle for a test drive to ensure the check engine light does not reappear.