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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to ensure safety while working on the vehicle.
• Raise the vehicle and secure it on jack stands.

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors.
  2. Disconnect the wiring harness from each sensor.
  3. Using a socket wrench, remove the oxygen sensors from the exhaust system.
  4. Install new oxygen sensors and torque them to manufacturer specifications (typically around 30 lb-ft).
  5. Reconnect the wiring harness to the sensors.

3. Inspect and Replace Catalytic Converter

• Sub-steps:
  1. Inspect the catalytic converter for any physical damage or signs of clogging.
  2. If replacement is required, unbolt the catalytic converter from the exhaust system using a socket wrench.
  3. Install the new catalytic converter and align it properly.
  4. Torque the bolts to the specified value (usually around 40 lb-ft).
  5. Reconnect any exhaust hangers or brackets.

4. Reconnect Battery and Clear Codes

• Sub-steps:
  1. Reconnect the battery terminals.
  2. Use the OBD-II scanner to clear the P0420 code.
  3. Start the engine and allow it to reach operating temperature.