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

Solution

1. Preparation

• Gather tools and parts needed for repair.
• Safety gear: gloves and safety glasses.
• Disconnect the battery to avoid electrical issues during the repair.

2. Replace Oxygen Sensors (if necessary)

1. Locate the upstream and downstream oxygen sensors.
2. Use an O2 sensor socket to carefully remove the faulty sensor(s).
3. Install new oxygen sensors, tightening them to the manufacturer's specifications (typically around 30 ft-lbs).
4. Reconnect the wiring harness for each sensor.

3. Inspect and Replace Catalytic Converter (if necessary)

1. Remove the exhaust heat shield (if applicable) using a socket set.
2. Disconnect the exhaust piping from the catalytic converter. Use a wrench to loosen the clamps and bolts.
3. Remove any mounting bolts securing the catalytic converter to the exhaust manifold or exhaust pipe.
4. Carefully remove the old catalytic converter.
5. Install the new catalytic converter, ensuring proper alignment and secure it with bolts to the manufacturer’s torque specifications (usually around 30-40 ft-lbs).
6. Reconnect the exhaust piping and secure with clamps.

4. Reconnect Battery and Clear Codes

1. Reconnect the battery terminals.
2. Use an OBD-II scanner to clear the P0420 code from the system.
3. Start the engine and allow it to reach operating temperature.