how to fix P0420 code in Toyota RAV4 Fifth Generation (2019-present)

Solution

1. Preparation

• Gather required tools and parts.
• Disconnect the battery to prevent electrical shorts.
• Allow the exhaust system to cool down before starting work.

2. Inspect and Replace O2 Sensors

• Check the upstream O2 sensor (sensor 1) and downstream O2 sensor (sensor 2) for any signs of wear or damage.
• If faulty, remove the O2 sensors using an O2 sensor socket.
• Install new O2 sensors, ensuring they are tightened to manufacturer specifications (typically around 30 lb-ft).
• Reconnect the electrical connectors.

3. Inspect and Replace the Catalytic Converter

• If the O2 sensors are functioning properly, inspect the catalytic converter for physical damage.
• Remove the exhaust heat shield if necessary to access the catalytic converter.
• Unbolt the catalytic converter from the exhaust manifold and the exhaust pipe. Use penetrating oil on stubborn bolts if needed.
• Install the new catalytic converter, ensuring all gaskets are replaced, and torque bolts to manufacturer's specifications (typically around 25 lb-ft).
• Reattach any heat shields removed during the process.

4. Clear Codes and Test Drive

• Reconnect the battery.
• Use the OBD-II scanner to clear any fault codes from the ECU.
• Start the engine and allow it to warm up.
• Perform a test drive to monitor for any reoccurrence of the P0420 code.