my Toyota RAV4 XA50 (2019-2024) has a check engine light with code P0420, what should I check?

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the vehicle battery to ensure safety during repairs.
• Tools Required: OBD-II scanner, multimeter, socket set, torque wrench.

2. Inspect and Replace Oxygen Sensors (if necessary)

• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors in the exhaust system.
  2. Disconnect the electrical connectors from both sensors.
  3. Use a socket wrench to remove the sensors from the exhaust system.
  4. Install new oxygen sensors by screwing them into place and tightening them to the manufacturer’s specified torque (usually around 30 lb-ft).
  5. Reconnect the electrical connectors securely.

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

• Sub-steps:
  1. Identify the catalytic converter's location along the exhaust system.
  2. Remove any heat shields or brackets holding the catalytic converter.
  3. Use a socket wrench to unbolt the catalytic converter from the exhaust pipes.
  4. Inspect the old catalytic converter for damage, such as cracking or excessive soot buildup.
  5. Install the new catalytic converter by reversing the removal steps, ensuring all bolts are tightened to manufacturer specifications.
  6. Reinstall any heat shields or brackets removed during the process.