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

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the vehicle battery to ensure safety during electrical work.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench

• Remove the upstream oxygen sensor:

  1. Locate the upstream O2 sensor on the exhaust manifold.
  2. Use an O2 sensor socket to unscrew and remove the sensor.
  3. Inspect the sensor for damage; replace if necessary.

• Install the new upstream O2 sensor:

  1. Apply anti-seize compound to the threads (if not pre-applied).
  2. Torque to manufacturer specifications (usually around 30 lb-ft).

• Repeat the process for the downstream O2 sensor:

  1. Locate the downstream O2 sensor after the catalytic converter.
  2. Remove and replace as described above.

3. Inspect and Replace the Catalytic Converter

• Tools Required: Socket set, torque wrench, exhaust hanger tool

• Inspect the catalytic converter visually for damage:

  1. Look for dents, cracks, or rust.
  2. Check for rattling noises indicating internal failure.

• If replacement is necessary:

  1. Disconnect the exhaust pipes from the catalytic converter using a socket set.
  2. Remove any exhaust hangers with an exhaust hanger tool.
  3. Remove the old catalytic converter and replace it with a new one.
  4. Reconnect the exhaust system, ensuring all bolts are torqued to specifications (usually around 30 lb-ft).

4. Clear Codes and Test

1. Reconnect the battery and use an OBD-II scanner to clear the P0420 code.
2. Start the engine and allow it to reach operating temperature.
3. Conduct a test drive to monitor for any reoccurrence of the code.