how to resolve 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 parking brake is engaged.
• Disconnect the battery to prevent any electrical issues during repairs.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench
• Remove the upstream oxygen sensor using the O2 sensor socket.
• Inspect the sensor for contamination or damage; replace if necessary.
• Install the new sensor and torque to manufacturer specifications (usually around 30-40 lb-ft).
• Repeat the process for the downstream oxygen sensor if it shows signs of failure.

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, exhaust pipe cutter (if needed)
• Remove the exhaust heat shield to access the catalytic converter.
• Disconnect the exhaust pipe from the catalytic converter, noting the arrangement of any gaskets.
• Remove the catalytic converter from its mounting points.
• Install the new catalytic converter, ensuring proper alignment and securing all bolts to the manufacturer’s torque specifications.
• Reattach the exhaust heat shield.

4. Reconnect Battery and Clear Codes

• Reconnect the battery terminals.
• Use the OBD-II scanner to clear the P0420 code and reset the check engine light.