how to fix P0420 code on Toyota Highlander XU70 (2020-Present)

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the battery to ensure safety while working on electrical components.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench.
• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors in the exhaust system.
  2. Using the O2 sensor socket, carefully unscrew the sensors from their positions.
  3. Inspect the sensors for signs of damage or contamination.
  4. Install the new sensors and torque them to the manufacturer's specifications (typically around 30 lb-ft).
  5. Reconnect the electrical connectors firmly to ensure a good connection.

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, jack and jack stands, exhaust gasket (if applicable).
• Sub-steps:
  1. Raise the vehicle using a jack and secure it with jack stands.
  2. Locate the catalytic converter and inspect it for signs of physical damage or excessive carbon buildup.
  3. If replacement is needed, disconnect the exhaust pipes from the catalytic converter using the appropriate socket.
  4. Remove any mounting brackets or hangers holding the catalytic converter in place.
  5. Install the new catalytic converter, ensuring that any gaskets are properly positioned.
  6. Reconnect the exhaust system and tighten all connections securely.

4. Reset Check Engine Light

• Tools Required: OBD-II scanner.
• Sub-steps:
  1. Reconnect the battery if it was disconnected.
  2. Use the OBD-II scanner to clear the P0420 code from the engine control module (ECM).
  3. Start the engine and allow it to reach operating temperature.