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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to ensure safety while working with the electrical components.

2. Inspect and Replace Oxygen Sensors (if faulty)

• Tools Required: O2 sensor socket, ratchet, torque wrench.
• Remove the upstream and downstream oxygen sensors using the O2 sensor socket.
• Inspect the sensor connectors for corrosion or damage. Clean or replace as necessary.
• Install new oxygen sensors and torque them to the manufacturer’s specifications (typically around 30 ft-lbs).

3. Inspect and Replace Catalytic Converter

• Tools Required: Socket set, jack and jack stands, exhaust pipe cutter (if necessary), gasket scraper.
• Raise the vehicle using a jack and secure it with jack stands.
• Remove the exhaust pipe connected to the catalytic converter using a socket set. Cut the pipe if it is too corroded to remove.
• Remove any heat shields or brackets holding the catalytic converter in place.
• Install the new catalytic converter, ensuring it is properly aligned and supported.
• Reattach the exhaust pipe and torque all connections to manufacturer specifications.

4. Reconnect Battery and Clear Codes

• Reconnect the negative battery terminal.
• Use the OBD-II scanner to clear the P0420 code from the ECU.