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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to prevent electrical shock.
• Allow the vehicle to cool down completely.

2. Inspect and Replace Oxygen Sensors

• Locate the upstream (pre-catalytic converter) and downstream (post-catalytic converter) oxygen sensors.
• Use a socket wrench to remove the old oxygen sensors.
• Install new oxygen sensors, ensuring they are torqued to the manufacturer's specifications (typically around 30 Nm).
• Reconnect the wiring harness.

3. Inspect and Replace Catalytic Converter (if necessary)

• Remove the exhaust pipe bolts using a socket set and wrench.
• Carefully detach the catalytic converter from the exhaust system.
• Inspect the catalytic converter for damage or blockage.
• If replacement is needed, install a new catalytic converter, ensuring proper alignment.
• Torque bolts to manufacturer specifications (generally around 40 Nm).

4. Clear Error Codes

• Reconnect the battery.
• Use the OBD-II scanner to clear any stored error codes.
• Start the engine and let it idle for a few minutes.

5. Test Drive

• Conduct a test drive to ensure the vehicle operates smoothly and the check engine light does not reappear.