how to troubleshoot P0420 code on my Toyota Camry Eighth Generation (2018-present)

Solution

1. Preparation

• Gather tools and necessary parts.
• Disconnect the battery to prevent electrical shorts.
• Allow the engine to cool before working on exhaust components.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench, penetrating oil.
• Locate the upstream and downstream oxygen sensors on the exhaust system.
• Apply penetrating oil to the sensor threads and wait for a few minutes.
• Disconnect the electrical connectors from both sensors.
• Use the O2 sensor socket to remove the sensors from the exhaust.
• Install new oxygen sensors, tightening them to the manufacturer’s specified torque (usually around 30 lb-ft).
• Reconnect the electrical connectors.

3. Inspect and Replace the Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, exhaust gasket.
• If the catalytic converter shows signs of damage, remove the exhaust pipe bolts securing it to the exhaust manifold.
• Support the exhaust system to prevent it from hanging.
• Remove the catalytic converter from its mounting brackets and disconnect it from the exhaust pipe.
• Install the new catalytic converter, ensuring the gasket is in place.
• Torque the bolts to the manufacturer’s specifications.

4. Clear Codes and Test Drive

• Reconnect the battery.
• Use the OBD-II scanner to clear the P0420 code.
• Start the vehicle and conduct a test drive to ensure the check engine light does not reappear.