how to fix P0420 code in my Toyota Camry XV70 (2018-2024)

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is off.
• Disconnect the battery to avoid electrical shorts.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, wrench set, multimeter.
• Remove the upstream oxygen sensor using the O2 sensor socket.
• Check the resistance and voltage output with a multimeter; replace if faulty.
• Repeat the process for the downstream oxygen sensor, ensuring proper installation of the new sensor.

3. Inspect and Clean Catalytic Converter

• Tools Required: Exhaust system cleaner, brush, safety goggles, gloves.
• Remove the exhaust pipe connected to the catalytic converter by loosening the clamps and bolts.
• Inspect the catalytic converter for physical damage or clogging.
• If cleanable, apply exhaust system cleaner and scrub gently; rinse with water and allow to dry.
• If damaged or excessively clogged, replace the catalytic converter with a new unit.

4. Reinstall Exhaust Components

• Reattach the exhaust pipe to the catalytic converter and secure with clamps and bolts.
• Ensure all connections are tight and free from leaks.

5. Reconnect Battery and Test

• Reconnect the battery terminals.
• Start the engine and allow it to reach operating temperature.
• Clear the error codes using the OBD-II scanner and check if the P0420 code reappears after a test drive.