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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to prevent electrical shorts during repair.
• Allow the engine to cool completely before starting work.

2. Replace O2 Sensors (if faulty)

• Tools Required: O2 sensor socket, wrench, penetrating oil.
• Sub-steps:
  1. Locate the upstream and downstream O2 sensors on the exhaust manifold and catalytic converter.
  2. Apply penetrating oil to the sensor threads if they are stuck.
  3. Use the O2 sensor socket to remove the faulty sensors by turning counterclockwise.
  4. Install the new O2 sensors by threading them in and tightening to the manufacturer's torque specification (usually around 30 lb-ft).

3. Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, gasket scraper, new exhaust gaskets.
• Sub-steps:
  1. Remove any heat shields or brackets securing the catalytic converter.
  2. Disconnect the exhaust pipe from the catalytic converter by removing the bolts or clamps.
  3. Remove the catalytic converter from its mounting points.
  4. Clean the mounting surfaces to ensure a proper seal with the new converter.
  5. Install the new catalytic converter, using new gaskets and tightening bolts to the manufacturer’s torque specifications (usually around 30-40 lb-ft).

4. Reconnect Battery

• Reconnect the negative terminal of the battery once all repairs are complete.