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

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the battery by removing the negative terminal.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench
• Remove the upstream oxygen sensor located before the catalytic converter.
  • Use the O2 sensor socket to unscrew it.
• Install the new upstream oxygen sensor.
  • Torque to manufacturer's specification (typically around 30 ft-lbs).
• Repeat for the downstream oxygen sensor if faulty or if the readings were inconsistent.

3. Examine and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, cutting tool, welding equipment (if required)
• Remove the exhaust pipe connected to the catalytic converter.
• Unbolt the catalytic converter from the exhaust manifold and the exhaust pipe. Inspect for any signs of damage.
• Install the new catalytic converter.
  • Ensure all gaskets are new and properly fitted.
  • Torque bolts to manufacturer's specifications.
• Reattach the exhaust pipe and ensure all connections are secure.

4. Reset the Engine Control Module (ECM)

• Reconnect the battery's negative terminal.
• Use the OBD-II scanner to clear the P0420 code from the ECM.