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

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the battery to ensure safety while working on electrical components.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, wrench, penetrating oil.
• Remove the upstream O2 sensor (usually located before the catalytic converter) using the O2 sensor socket.
• Inspect the sensor for contamination or damage. Replace it if necessary.
• Repeat the process for the downstream O2 sensor (located after the catalytic converter).
• Note: Make sure to apply anti-seize compound on the threads of the new sensors before installation.

3. Inspect and Replace Catalytic Converter

• Tools Required: Socket set, jack and jack stands, exhaust gasket (if needed).
• Safely lift the vehicle using a jack and secure it with jack stands.
• Remove the bolts securing the catalytic converter to the exhaust system using a socket set.
• Inspect the condition of the catalytic converter for any signs of blockage or damage.
• If damaged, replace the catalytic converter with a new unit, ensuring it meets OEM specifications.
• Reinstall any bolts and gaskets necessary to seal the exhaust system properly.

4. Reset the Engine Control Module (ECM)

• Reconnect the battery and use an OBD-II scanner to clear the P0420 code from the ECM.
• Start the engine and allow it to idle for a few minutes to reset system parameters.