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

Solution

1. Preparation

• Gather all tools and parts required.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the battery's negative terminal to avoid electrical shock.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench
• Remove the upstream (pre-catalytic) oxygen sensor:
  1. Locate the sensor on the exhaust manifold or pipe.
  2. Use the O2 sensor socket to unscrew it.
  3. Install the new oxygen sensor and tighten it to the manufacturer's specified torque (typically around 30 ft-lbs).
• Repeat for the downstream (post-catalytic) oxygen sensor if necessary.

3. Inspect and Clean/Replace Catalytic Converter

• Tools Required: Socket set, torque wrench, exhaust gasket (if needed)
• If the catalytic converter shows signs of damage or blockage:
  1. Remove the exhaust pipes connected to the catalytic converter.
  2. Inspect for any physical damage or heavy carbon buildup.
  3. If cleaning, use a catalytic converter cleaner; if replacement is necessary, install a new catalytic converter, ensuring to use the correct gaskets.
  4. Torque the bolts to the manufacturer's specifications.

4. Clear Codes and Test Drive

• Reconnect the battery and clear the trouble codes using the OBD-II scanner.
• Test drive the vehicle for at least 20 miles under various driving conditions to monitor for any reoccurrence of the P0420 code.