how to fix P0420 code in Toyota Corolla E210 (2019-2024)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to ensure safety while working on electrical components.
• Raise the vehicle using jack stands if necessary to access the exhaust system.

2. Inspect and Replace O2 Sensors

• Tools Required: O2 sensor socket, torque wrench.
• Remove the pre-catalytic O2 sensor:
  1. Disconnect the electrical connector.
  2. Use the O2 sensor socket to unscrew the sensor from the exhaust pipe.
• Install the new O2 sensor:
  1. Apply anti-seize compound to the threads of the new sensor.
  2. Screw the new sensor in place and torque it to the manufacturer's specification (typically around 30 ft-lbs).
  3. Reconnect the electrical connector.
• Repeat for the post-catalytic O2 sensor if it shows signs of malfunction.

3. Inspect and Replace Catalytic Converter

• Tools Required: Socket set, torque wrench, exhaust gasket.
• Remove the catalytic converter:
  1. Unbolt the catalytic converter from the exhaust manifold and exhaust pipe using the socket set.
  2. If the converter is welded in, use a cutting tool to remove it carefully.
• Install the new catalytic converter:
  1. Position the new converter in place.
  2. Use new gaskets as needed and torque the bolts to the manufacturer's specifications (typically around 30 ft-lbs).

4. Final Checks

• Reconnect the battery.
• Clear the diagnostic trouble codes using the OBD-II scanner.
• Start the engine and check for any exhaust leaks around the new components.