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

Solution

1. Preparation

• Gather tools and parts: OBD-II scanner, multimeter, socket set, torque wrench, replacement catalytic converter (if needed), oxygen sensors (if needed).
• Safety precautions: Disconnect the battery before starting any electrical work. Allow the engine to cool before working on the exhaust system.

2. Inspect and Replace Oxygen Sensors (if necessary)

• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors on the exhaust manifold and after the catalytic converter, respectively.
  2. Disconnect the electrical connectors from both sensors.
  3. Use a socket to remove the sensors from their mounting locations.
  4. Install new sensors by threading them into the exhaust and tightening to manufacturer specifications (typically around 30 Nm).
  5. Reconnect the electrical connectors.

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

• Sub-steps:
  1. Disconnect the battery again if it was reconnected.
  2. Remove the exhaust heat shield if applicable.
  3. Unbolt the catalytic converter from the exhaust system using a socket set (ensure to note the orientation for reinstallation).
  4. Inspect the old catalytic converter for damage and blockage. If damaged, replace it with a new OEM or high-quality aftermarket unit.
  5. Install the new catalytic converter, ensuring all mounting bolts are torqued to manufacturer specifications (usually around 40-60 Nm).
  6. Reinstall any heat shields removed during the process.

4. Clear the Codes and Test

• Sub-steps:
  1. Reconnect the battery.
  2. Use the OBD-II scanner to clear the P0420 code from the vehicle’s computer.
  3. Start the engine and let it reach operating temperature.
  4. Take the vehicle for a test drive under various conditions to ensure the check engine light does not reappear.