my Toyota RAV4 XA50 (2019-2024) engine light is on with code P0420, what does it mean?

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors on the exhaust manifold and catalytic converter.
  2. Detach the electrical connectors from both sensors.
  3. Use a wrench to unscrew and remove the sensors from their mounting points.
  4. Install new oxygen sensors (ensure they are the correct type for your vehicle).
  5. Reconnect the electrical connectors securely.

3. Check and Clean Catalytic Converter

• Sub-steps:
  1. Inspect the catalytic converter for physical damage or clogging.
  2. If applicable, use a catalytic converter cleaning product according to manufacturer’s instructions.
  3. If the converter is severely damaged or clogged, remove it by unscrewing the mounting bolts and disconnecting it from the exhaust system.
  4. Replace with a new catalytic converter that meets OEM specifications.

4. Reconnect Battery and Clear Codes

• Sub-steps:
  1. Reconnect the negative battery terminal.
  2. Use the OBD-II scanner to clear the P0420 code from the vehicle's computer.
  3. Perform a test drive to ensure the code does not reappear.