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

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Ensure the vehicle is parked on a level surface and the engine is off and cool.
• Disconnect the negative battery terminal to avoid electrical shorts.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench
• Remove the downstream oxygen sensor:
  1. Locate the downstream oxygen sensor (after the catalytic converter).
  2. Use the O2 sensor socket to unscrew the sensor from the exhaust pipe.
  3. Inspect the sensor for corrosion or damage.
• Install the new downstream oxygen sensor:
  1. Apply anti-seize compound to the threads of the new sensor.
  2. Screw the new sensor into place and tighten to manufacturer specifications (usually around 30 lb-ft).

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, jack and jack stands, exhaust hanger removal tool
• Remove the catalytic converter:
  1. Raise the vehicle safely using jack stands.
  2. Disconnect the exhaust pipe from the catalytic converter using the socket set.
  3. Remove any exhaust hangers using the exhaust hanger removal tool.
  4. Take out the catalytic converter from the vehicle.
• Install the new catalytic converter:
  1. Position the new catalytic converter in place.
  2. Reattach the exhaust pipe and secure it with bolts to the correct torque specifications.
  3. Reinstall exhaust hangers if they were removed.

4. Reconnect Battery and Clear Codes

• Reconnect the negative battery terminal.
• Use the OBD-II scanner to clear the P0420 code and check for any additional codes.
• Start the engine and allow it to reach operating temperature.