how to fix P0420 code on my Toyota Corolla E170 (2013-2019)

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Inspect and Replace O2 Sensors

1. Locate the upstream and downstream oxygen sensors.
2. Use a socket wrench to remove the upstream O2 sensor from the exhaust manifold.
3. Install the new upstream O2 sensor; torque it to the manufacturer's specifications (typically around 30-40 lb-ft).
4. Repeat the process for the downstream O2 sensor, if needed.

3. Replace the Catalytic Converter (if necessary)

1. Use a socket set to unbolt the catalytic converter from the exhaust system.
2. Remove any hangers or brackets securing the catalytic converter.
3. Install the new catalytic converter, ensuring proper alignment with exhaust pipes.
4. Torque all bolts to the manufacturer's specifications.
5. Reattach any hangers or brackets.

4. Reconnect Battery and Clear Codes

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