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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical issues.
• Allow the vehicle to cool down if the engine has been running.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench, penetrating oil
• 1. Locate the upstream and downstream oxygen sensors (typically found on the exhaust manifold and after the catalytic converter).
• 1. Spray penetrating oil on the sensor threads and let it sit for a few minutes.
• 1. Using the O2 sensor socket, carefully remove both sensors.
• 1. Install new oxygen sensors, hand-tighten, and then torque to manufacturer specifications (usually around 30 lb-ft).

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Wrench set, jack and jack stands, socket set, torque wrench
• 1. Raise the vehicle securely using jack stands.
• 1. Disconnect the exhaust pipes from the catalytic converter using the appropriate socket or wrench.
• 1. Remove the mounting bolts securing the catalytic converter to the exhaust system.
• 1. Install the new catalytic converter, ensuring all gaskets are in place to prevent leaks.
• 1. Torque the mounting bolts to manufacturer specifications (usually around 30 lb-ft).
• 1. Reconnect the exhaust pipes and ensure all connections are secure.

4. Clear Error Codes

• Reconnect the negative battery terminal.
• Use the OBD-II scanner to clear the P0420 code and any other codes that may have been stored.