how to fix my Toyota RAV4 Fifth Generation (2019-present) check engine light P0420 code

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to ensure safety while working on the electrical systems.
  • Tools Required: OBD-II scanner, multimeter, socket set, torque wrench, jack and jack stands.

2. Inspect and Test Oxygen Sensors

• Remove the upstream (pre-catalytic converter) oxygen sensor.
  • Use a socket wrench to unscrew the sensor.
• Test the sensor's resistance and output voltage with a multimeter.
  • Sub-step: If faulty, replace the oxygen sensor.
• Reinstall the sensor, ensuring proper torque (typically 30-40 ft-lbs).

3. Inspect Catalytic Converter

• Check the catalytic converter for any signs of physical damage or blockage.
• If necessary, replace the catalytic converter.
  • Sub-steps:
    • Remove the exhaust pipes connected to the catalytic converter using a socket set.
    • Unbolt the catalytic converter from its mounting points.
    • Install a new catalytic converter, ensuring proper alignment and securing with bolts.
    • Torque bolts to manufacturer specifications (typically around 30-40 ft-lbs).

4. Clear Diagnostic Codes

• Reconnect the battery and use the OBD-II scanner to clear the P0420 code from the vehicle's computer.

5. Recheck System

• Start the vehicle and allow it to idle for a few minutes.
• Use the OBD-II scanner again to ensure the check engine light remains off and no new codes have appeared.