how to fix P0420 code on my Toyota Corolla E170 (2013-2019)

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the battery to prevent electrical shorts during work.
• Allow the vehicle to cool down before working on the exhaust system.

2. Inspect and Replace Oxygen Sensors

• Tools Needed: O2 sensor socket, torque wrench
• Remove the upstream and downstream oxygen sensors.
  • Disconnect the wiring harness from each sensor.
  • Use the O2 sensor socket to unscrew and remove the sensors.
• Install new oxygen sensors.
  • Apply anti-seize compound to the threads of the new sensors (if required).
  • Torque the sensors to the manufacturer's specifications (typically around 30 lb-ft).
• Reconnect the wiring harnesses securely.

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Needed: Socket set, jack and jack stands, exhaust gasket sealant
• Raise the vehicle using a jack and secure it with jack stands.
• Remove the bolts securing the catalytic converter to the exhaust pipe and the exhaust manifold.
• Carefully detach the catalytic converter from the exhaust system.
• Clean the mating surfaces on the exhaust pipe and manifold.
• Install the new catalytic converter and secure it with bolts to the exhaust system.
  • Use exhaust gasket sealant if recommended.
  • Torque bolts to manufacturer's specifications.

4. Clear Codes and Test

• Tools Needed: OBD-II scanner
• Reconnect the battery.
• Use the OBD-II scanner to clear the P0420 code.
• Start the engine and let it run for a few minutes to ensure the system is functioning properly.