how to fix the P0420 code on my Toyota RAV4 Fifth Generation (2019-present)

Solution

1. Preparation

• Gather tools and parts: OBD-II scanner, multimeter, socket set, torque wrench, oxygen sensor socket, and replacement catalytic converter if necessary.
• Ensure the vehicle is parked on a level surface and the engine is off. Disconnect the battery.

2. Inspect and Test Oxygen Sensors

• Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
• Using a multimeter, check the voltage output of the upstream oxygen sensor; it should fluctuate between 0.1 and 0.9 volts.
• If the sensor is not functioning correctly, replace it with a new one.

3. Inspect Catalytic Converter

• Remove the exhaust heat shield if applicable.
• Visually inspect the catalytic converter for signs of physical damage, such as dents or excessive rust.
• If damage is found, proceed to replace the catalytic converter.

4. Replace Catalytic Converter (if necessary)

• Remove the bolts securing the catalytic converter to the exhaust system using a socket set.
• Carefully detach the catalytic converter from the exhaust system and exhaust manifold.
• Install the new catalytic converter in the reverse order of removal, ensuring all gaskets are replaced and bolts are tightened to the manufacturer's torque specifications.

5. Clear Error Codes and Reconnect Battery

• Reconnect the battery and use the OBD-II scanner to clear the P0420 code.
• Start the engine and let it reach operating temperature to ensure the system is functioning properly.