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

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shock.
• Allow the exhaust system to cool before starting work.

2. Inspect and Test Oxygen Sensors

1. Remove the upstream oxygen sensor: Use an O2 sensor socket or a wrench to unscrew the sensor from the exhaust manifold.
2. Test the sensor: Connect the multimeter to the sensor's connector and check the voltage output (should fluctuate between 0.1 and 0.9 volts).
3. Replace the sensor if faulty: If the sensor is not functioning properly, replace it with a new one.

3. Inspect and Replace the Catalytic Converter

1. Remove the exhaust heat shield: If applicable, unscrew and remove the heat shield covering the catalytic converter.
2. Unbolt the catalytic converter: Use a socket set to remove bolts securing the catalytic converter to the exhaust system.
3. Inspect the converter: Check for physical damage or excessive carbon buildup. If damaged, replace with a new catalytic converter.
4. Install the new catalytic converter: Position the new unit and secure it with bolts. Torque to manufacturer specifications (typically around 30-40 lb-ft).
5. Reinstall the heat shield: If applicable, reattach the heat shield.

4. Reconnect Battery and Clear Codes

1. Reconnect the negative battery terminal.
2. Use the OBD-II scanner: Clear the P0420 code from the vehicle's computer.