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

Solution

1. Preparation

• Gather tools and parts: OBD-II scanner, multimeter, socket set, torque wrench, replacement oxygen sensors (if needed), and a new catalytic converter (if necessary).
• Disconnect the battery negative terminal to prevent electrical shorts.
• Allow the engine to cool before starting work.

2. Inspect and Repair Exhaust System

• Sub-steps:
  1. Lift the vehicle securely using jack stands.
  2. Visually inspect the exhaust pipes, joints, and catalytic converter for signs of leaks or damage.
  3. Use exhaust repair tape or sealant to fix minor leaks or replace damaged exhaust components.

3. Replace Oxygen Sensors (if necessary)

• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors (usually found before and after the catalytic converter).
  2. Disconnect the electrical connectors from both sensors.
  3. Use a socket wrench to remove the sensors from the exhaust pipe.
  4. Install the new sensors by threading them into place and tightening them to the manufacturer's torque specifications (typically around 30 ft-lbs, check specific values).
  5. Reconnect the electrical connectors.

4. Replace Catalytic Converter (if necessary)

• Sub-steps:
  1. Remove any heat shields or brackets securing the catalytic converter.
  2. Unbolt the catalytic converter from the exhaust system using a socket set.
  3. Install the new catalytic converter and secure it with bolts, tightening to the specified torque (usually 40-45 ft-lbs).
  4. Reinstall any heat shields or brackets removed earlier.

5. Reset the Check Engine Light

• Sub-steps:
  1. Reconnect the battery negative terminal.
  2. Use the OBD-II scanner to clear the P0420 code from the vehicle's computer.