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

Solution

1. Preparation

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

2. Inspect and Repair Exhaust Leaks

• Tools Required: Socket set, gasket scraper
• Inspect the exhaust manifold and connections for leaks.
• If any cracks or holes are found, repair or replace the affected sections.

3. Replace Faulty Oxygen Sensors

• Tools Required: O2 sensor socket, torque wrench
• Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
• Disconnect the electrical connectors from both sensors.
• Remove the sensors using the O2 sensor socket, and install new sensors, tightening them to the manufacturer's specified torque (typically around 30 lb-ft).
• Reconnect the electrical connectors securely.

4. Replace the Catalytic Converter (if necessary)

• Tools Required: Cutting torch (if welding is required), socket set, exhaust hanger removal tool
• Remove the exhaust system components leading to the catalytic converter. Support the exhaust with a jack or stands.
• Disconnect the catalytic converter from the exhaust manifold and the downstream section.
• Replace with a new catalytic converter, ensuring all connections are tight and secure. Reinstall any exhaust hangers.
• If welding is required, ensure proper techniques are used to prevent exhaust leaks.

5. Reconnect Battery and Clear Codes

• Reconnect the battery terminals.
• Use the OBD-II scanner to clear the P0420 code from the engine control module.
• Start the engine and allow it to run for a few minutes to check for any reoccurrence of the code.