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

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Ensure the vehicle is parked on a flat surface, and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench
• Remove the upstream and downstream oxygen sensors using the O2 sensor socket.
• Inspect the old sensors for damage or contamination.
• Install new oxygen sensors, applying anti-seize compound to the threads. Torque to manufacturer specifications (typically around 30 lb-ft).

3. Examine and Replace Catalytic Converter

• Tools Required: Socket set, wrench set, exhaust hanger removal tool
• Remove the exhaust hangers to free the exhaust system.
• Loosen and remove bolts connecting the catalytic converter to the exhaust pipes.
• Carefully remove the catalytic converter and inspect for internal damage or blockage.
• Install a new catalytic converter, ensuring all gaskets are in place. Torque bolts to manufacturer specifications.

4. Reassemble and Recheck Connections

• Reattach the exhaust hangers and check all connections for tightness.
• Reconnect the negative battery terminal.
• Start the vehicle and allow it to reach operating temperature.