how to fix P0420 code on my 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. Replace Faulty Oxygen Sensors

• Tools Required: O2 sensor socket, torque wrench, penetrating oil.
• Use penetrating oil on the O2 sensor threads to help with removal.
• Disconnect the electrical connectors from the faulty sensors.
• Remove the sensors using the O2 sensor socket.
• Install the new sensors and torque to manufacturer specifications (typically around 30 ft-lbs).
• Reconnect electrical connectors.

3. Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, exhaust hanger removal tool, gasket scraper.
• Raise the vehicle securely on jack stands.
• Remove the exhaust hangers using the exhaust hanger removal tool.
• Disconnect the exhaust pipes leading to the catalytic converter.
• Remove the catalytic converter by unbolting it from the exhaust manifold and the downstream pipe.
• Clean the mating surfaces where the new catalytic converter will be installed.
• Install the new catalytic converter and torque bolts to manufacturer specifications (usually around 30-40 ft-lbs).
• Reattach the exhaust hangers.

4. Clear Codes

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