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

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is off.
• Disconnect the battery before starting repairs.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, torque wrench, penetrating oil.
• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors on the exhaust manifold and catalytic converter.
  2. Apply penetrating oil to the sensor threads to ease removal.
  3. Disconnect the electrical connectors of both oxygen sensors.
  4. Use the O2 sensor socket to remove the sensors from the exhaust system.
  5. Install new oxygen sensors, ensuring they are torqued to manufacturer specifications (typically around 30 ft-lbs).
  6. Reconnect the electrical connectors.

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

• Tools Required: Socket set, cutting torch (if welding is needed), gasket scraper.
• Sub-steps:
  1. Remove the exhaust heat shield if present.
  2. Unbolt the catalytic converter from the exhaust system using a socket set.
  3. Inspect the catalytic converter for physical damage or blockage. If damaged, proceed with replacement.
  4. Install the new catalytic converter, ensuring proper alignment and secure all bolts to the specified torque.
  5. Replace any gaskets as needed to prevent exhaust leaks.

4. Clear Error Codes

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

5. Final Inspection

• Start the engine and allow it to reach operating temperature.
• Inspect for exhaust leaks around the repaired areas.