how to fix P0420 code on my Toyota Camry Eighth Generation (2018-present)

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the battery to avoid electrical shocks.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, wrench set, multimeter
• Remove the upstream oxygen sensor from the exhaust manifold using the O2 sensor socket.
• Use a multimeter to test the sensor's voltage output; replace the sensor if it's not functioning properly.
• Install the new upstream oxygen sensor, ensuring it is securely tightened to the manufacturer's specifications.
• Repeat this process for the downstream oxygen sensor if necessary.

3. Inspect and Replace the Catalytic Converter

• Tools Required: Socket set, torque wrench, exhaust gasket
• Remove the exhaust piping connected to the catalytic converter by loosening the bolts.
• Inspect the catalytic converter for signs of damage or clogging.
• Replace the catalytic converter if it is found to be faulty or clogged, using a new exhaust gasket during installation.
• Reinstall the exhaust piping and tighten bolts to the manufacturer's torque specifications.

4. Clear Codes and Test Drive

• Reconnect the battery and use the OBD-II scanner to clear the P0420 code.
• Start the vehicle and let it idle, then take it for a test drive to ensure proper operation and to monitor for any return of the check engine light.