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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.
• Allow the engine to cool down before starting work.

2. Inspect and Replace Oxygen Sensors

1. Inspect Sensors

   • Locate the upstream (pre-catalytic converter) and downstream (post-catalytic converter) oxygen sensors.
   • Check for damaged wiring or connectors.

2. Remove Sensors

   • Use an oxygen sensor socket to carefully unscrew the sensors from their respective locations.
   • Be cautious not to damage the threads in the exhaust manifold or catalytic converter.

3. Install New Sensors

   • Apply anti-seize lubricant on the threads of the new oxygen sensors.
   • Install the new sensors and tighten them to the manufacturer’s specified torque (typically 30-40 ft-lbs).

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

1. Remove Exhaust Components

   • Use a socket set to remove any bolts and brackets securing the catalytic converter.
   • Carefully detach any exhaust components connected to the converter.

2. Inspect the Catalytic Converter

   • Check for external damage, excessive soot, or signs of overheating.
   • If internal components are damaged (e.g., broken substrate), replace the catalytic converter.

3. Install New Catalytic Converter

   • Position the new catalytic converter and secure it using the original bolts or new hardware as needed.
   • Torque the bolts to the manufacturer’s specifications.

4. Clear Codes and Test Drive

1. Reconnect Battery

   • Reconnect the negative battery terminal.

2. Clear the P0420 Code

   • Use the OBD-II scanner to erase the stored trouble codes.

3. Test Drive

   • Drive the vehicle under various conditions (city and highway) to ensure proper functioning and to verify that the check engine light does not reappear.