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

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, socket set, jack and jack stands, exhaust pressure gauge, safety glasses, gloves.
• Ensure the vehicle is parked on a level surface with the engine off and cool.
• Disconnect the battery to avoid any electrical issues.

2. Inspect and Replace Oxygen Sensors

a. Remove the upstream oxygen sensor:

• Locate the upstream oxygen sensor (usually near the exhaust manifold).
• Use the appropriate socket to loosen and remove the sensor.
• Inspect the sensor for damage or contamination.

b. Install the new upstream oxygen sensor:

• Apply anti-seize compound on the threads of the new sensor (if applicable).
• Screw in the new sensor and tighten to the manufacturer’s specified torque (usually around 30 lb-ft).

c. Repeat for the downstream oxygen sensor:

• Locate and remove the downstream oxygen sensor using the same method.
• Install the new sensor with anti-seize compound and tighten to the specified torque.

3. Inspect and Replace the Catalytic Converter (if necessary)

a. Remove the old catalytic converter:

• Locate the catalytic converter and identify the mounting bolts.
• Use a socket set to remove the bolts connecting the converter to the exhaust system.
• Carefully detach the catalytic converter, ensuring not to damage surrounding components.

b. Install the new catalytic converter:

• Position the new catalytic converter in place.
• Align it with the exhaust system flanges and install new gaskets if required.
• Tighten all bolts to the manufacturer’s specified torque (typically around 30-40 lb-ft).

4. Reconnect Battery and Clear Error Codes

• Reconnect the battery terminals.
• Use the OBD-II scanner to clear the P0420 code from the vehicle’s computer.
• Start the engine and allow it to reach operating temperature.