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

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 to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench
• Sub-steps:
  1. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
  2. Unplug the electrical connectors from both sensors.
  3. Use the O2 sensor socket to remove the upstream O2 sensor first.
  4. Install the new upstream O2 sensor and torque to manufacturer specifications (typically around 30 lb-ft).
  5. Repeat the process for the downstream O2 sensor.

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Wrench set, socket set, jack and jack stands
• Sub-steps:
  1. Raise the vehicle using a jack and secure it with jack stands.
  2. Locate the catalytic converter in the exhaust system.
  3. Use a wrench to remove the bolts securing the catalytic converter to the exhaust pipes.
  4. Carefully detach the old catalytic converter from the exhaust system.
  5. Install the new catalytic converter, ensuring proper alignment with exhaust pipes.
  6. Torque the bolts to the specifications provided in the service manual (usually around 25 lb-ft).

4. Reconnect Battery and Clear Codes

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