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 negative battery terminal for safety.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, and torque wrench.

• Remove the upstream oxygen sensor from the exhaust manifold:

  1. Use the O2 sensor socket to unscrew the sensor.
  2. Install the new sensor and torque it to the manufacturer's specifications (typically around 30 ft-lbs).

• Repeat the process for the downstream oxygen sensor if it is faulty.

3. Inspect and Replace the Catalytic Converter

• Tools Required: Socket set, jack and jack stands, exhaust pipe cutter (if needed).
• Raise the vehicle using a jack and secure it with jack stands.
• Remove any heat shields or brackets securing the catalytic converter.
• Unbolt and remove the old catalytic converter from the exhaust system.
• Install the new catalytic converter, ensuring all gaskets are in place, and torque the bolts to manufacturer's specifications.

4. Clear the DTC

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