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

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the battery to prevent any electrical shorts during repairs.

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  • Remove the upstream (pre-catalytic) oxygen sensor using an oxygen sensor socket.
  • Inspect the sensor for damage or excessive carbon buildup.
  • Install a new oxygen sensor and torque it to the manufacturer's specifications (typically around 30 lb-ft).
  • Repeat the process for the downstream (post-catalytic) oxygen sensor.

3. Inspect and Replace the Catalytic Converter

• Sub-steps:
  • Raise the vehicle safely on jack stands.
  • Remove exhaust hangers to free the catalytic converter.
  • Unbolt the catalytic converter from the exhaust manifold and the exhaust pipe.
  • Inspect the catalytic converter for any signs of clogging or damage.
  • Install a new catalytic converter, ensuring proper alignment and sealing.
  • Torque bolts to manufacturer specifications (usually around 40 lb-ft).

4. Clear Codes and Test Drive

• Sub-steps:
  • Reconnect the battery.
  • Use the OBD-II scanner to clear the P0420 code.
  • Start the engine and perform a test drive to ensure the issue is resolved.