how to address the P0420 code in my Toyota Highlander Fourth Generation (2020-present)?

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to prevent electrical shorts.
• Allow the exhaust system to cool before working on it.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench.
• Remove the upstream and downstream oxygen sensors using the O2 sensor socket.
• Inspect the sensors for contamination. If they show signs of damage, replace them.
• Install new sensors, ensuring they are torqued to the manufacturer’s specifications (typically around 30 lb-ft).

3. Check and Replace the Catalytic Converter

• Tools Required: Socket set, jack stands, exhaust pipe cutter (if necessary).
• Raise the vehicle safely using jack stands.
• Remove any heat shields covering the catalytic converter.
• Disconnect the exhaust pipes connected to the catalytic converter.
• If the catalytic converter is damaged or clogged, remove it and replace it with a new one.
• Ensure that all bolts are tightened to the specified torque settings.

4. Clear the Codes

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

5. Test Drive

• Conduct a test drive to ensure that the vehicle operates normally and that no codes reappear.