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

Solution

1. Preparation

• Gather tools and parts.
• Disconnect the vehicle battery to prevent electrical shorts.
• Ensure the car is on a level surface and secure it with jack stands if needed.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench.
• Remove the upstream oxygen sensor (pre-catalytic converter) by:
  1. Disconnecting the electrical connector.
  2. Using the O2 sensor socket to unscrew the sensor from the exhaust manifold.
• Replace it with a new sensor, torquing to manufacturer specifications (typically around 30 ft-lbs).
• Repeat the process for the downstream oxygen sensor (post-catalytic converter) if necessary.

3. Inspect and Replace the Catalytic Converter

• Tools Required: Socket set, torque wrench, cutting tool (if necessary).
• Inspect the catalytic converter for damage or excessive carbon buildup:
  1. If damaged, disconnect the exhaust pipes and remove the catalytic converter.
  2. Install the new catalytic converter, ensuring proper alignment.
  3. Torque all bolts to the specifications provided in the service manual.

4. Clear Codes and Test Drive

• Reconnect the battery.
• Use the OBD-II scanner to clear the P0420 code.
• Take the vehicle for a test drive to ensure the check engine light does not reappear.