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

Solution

1. Preparation

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

2. Inspect and Replace O2 Sensors

1. Locate the upstream and downstream O2 sensors.
2. Disconnect the electrical connectors from both sensors.
3. Use an O2 sensor socket to remove the sensors from the exhaust manifold and catalytic converter.
4. Install the new O2 sensors and torque them to the manufacturer's specifications (typically around 30-40 ft-lbs).
5. Reconnect the electrical connectors.

3. Clean or Replace Catalytic Converter

1. If the catalytic converter shows signs of clogging or physical damage, consider cleaning it using a catalytic cleaner or replacing it entirely.
2. For cleaning:
   • Use a catalytic converter cleaner according to the manufacturer’s instructions.
   • Allow the cleaner to work through the exhaust system as recommended.
3. For replacement:
   • Remove the old catalytic converter by unbolting it from the exhaust system.
   • Install the new catalytic converter and ensure all bolts are tightened to the specified torque (typically 30-35 ft-lbs).

4. Reconnect and Test

1. Reconnect the battery.
2. Start the engine and allow it to reach operating temperature.
3. Clear the P0420 code using the OBD-II scanner.
4. Conduct a test drive under various conditions to ensure no codes reappear.