how to fix P0420 code on my Toyota Corolla E140 (2006-2013)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative terminal of the battery to ensure safety while working on the electrical components.
• Raise the vehicle using a jack and secure it with jack stands.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, wrench set, torque wrench.
• Remove the upstream (pre-catalytic converter) and downstream (post-catalytic converter) oxygen sensors using an O2 sensor socket.
• Inspect the sensors for contamination or damage.
• Install new oxygen sensors and torque them to the manufacturer's specifications (usually around 30 ft-lbs).

3. Inspect and Replace Catalytic Converter

• Tools Required: Socket set, exhaust pipe cutter (if necessary), gasket scraper.
• Remove any heat shields or components obstructing access to the catalytic converter.
• Disconnect the exhaust pipes from the catalytic converter using a socket set.
• If necessary, cut the exhaust pipes to remove the old catalytic converter.
• Install the new catalytic converter and reattach the exhaust pipes. Ensure all connections are tight and properly sealed.

4. Clear Codes and Test Drive

• Reconnect the negative battery terminal.
• Use an OBD-II scanner to clear the P0420 code from the engine control module (ECM).
• Start the engine and allow it to reach operating temperature.
• Take the vehicle for a test drive to ensure the check engine light does not reappear.