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

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, jack and jack stands, socket set, torque wrench, safety glasses, gloves.
• Safety Warnings: Disconnect the battery before starting work on electrical systems. Allow the engine to cool before working on the exhaust system.

2. Inspect and Replace Oxygen Sensors

1. Locate the Oxygen Sensors:
   • Identify the upstream (pre-catalytic converter) and downstream (post-catalytic converter) oxygen sensors.
2. Disconnect the Sensors:
   • Carefully unplug the electrical connectors from both oxygen sensors.
3. Remove the Sensors:
   • Use a socket wrench to unscrew and remove the oxygen sensors from their respective locations.
4. Install New Oxygen Sensors:
   • Apply anti-seize compound to the threads of the new sensors.
   • Screw in the new sensors and tighten them to the manufacturer's specified torque (usually around 30 lb-ft).
5. Reconnect the Electrical Connectors:
   • Plug the connectors back into the new sensors.

3. Inspect and Replace Catalytic Converter (if necessary)

1. Inspect for Damage:
   • Check the catalytic converter for physical damage, such as dents or rust.
2. Remove the Exhaust Components:
   • Disconnect the exhaust pipes from the catalytic converter using a socket wrench.
3. Remove the Catalytic Converter:
   • Unbolt the catalytic converter from its mounting brackets and remove it from the exhaust system.
4. Install New Catalytic Converter:
   • Position the new catalytic converter and secure it with the mounting bolts.
   • Ensure all exhaust connections are tight and sealed.
5. Reconnect Exhaust Pipes:
   • Reattach any exhaust pipes removed during the process.