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

Solution

1. Preparation

• Gather all necessary tools and parts.
• Ensure the vehicle is on a flat surface, and the engine is cool.
• Disconnect the battery to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors

1. Locate the Oxygen Sensors:

   • Identify the locations of the upstream (pre-catalytic converter) and downstream (post-catalytic converter) oxygen sensors.

2. Remove the Sensors:

   • Use an oxygen sensor socket to carefully unscrew each sensor.
   • Disconnect the wiring harness from the sensors.

3. Install New Sensors:

   • Apply anti-seize compound on the threads of the new sensors.
   • Screw in the new sensors and reconnect the wiring harnesses, ensuring a secure fit.

3. Inspect and Replace the Catalytic Converter

1. Remove the Exhaust Components:

   • Using a socket set, unbolt the exhaust system components connected to the catalytic converter.
   • Support the exhaust with jack stands or a hoist if necessary.

2. Remove the Catalytic Converter:

   • Carefully detach the catalytic converter from its mounting brackets and exhaust pipes.
   • Inspect the old catalytic converter for any physical damage or clogging.

3. Install the New Catalytic Converter:

   • Position the new catalytic converter in place and secure it with the appropriate hardware.
   • Ensure all connections are tight to prevent exhaust leaks.

4. Reconnect Battery and Clear Codes

1. Reconnect the Battery:

   • Reattach the negative terminal of the battery securely.

2. Clear the OBD-II Codes:

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

3. Perform a Test Drive:

   • Drive the vehicle for a short distance to allow the engine control unit (ECU) to re-evaluate the system.