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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to prevent electrical shorts.
• Allow the engine to cool before starting work.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, multimeter.
• Remove the O2 sensor from the exhaust system using the O2 sensor socket.
• Test the sensor with a multimeter for correct voltage output while the engine is running.
• If faulty, replace it with a new sensor and ensure it fits the specifications for your Highlander.

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, exhaust pipe cutter (if needed).
• Remove the bolts securing the catalytic converter to the exhaust system.
• Inspect for any signs of damage or contamination.
• If replacing, install the new catalytic converter by reversing the removal process, ensuring all connections are tight and leak-free.
• Torque the bolts to the manufacturer’s specifications.

4. Clear Error Codes

• Reconnect the battery.
• Use the OBD-II scanner to clear the P0420 code and any other stored codes.
• Start the engine and allow it to reach operating temperature.