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

Solution

1. Preparation

• Gather all tools and parts required for the repair.
• Ensure the vehicle is parked on a level surface and the engine is off.
• Disconnect the negative battery terminal to prevent electrical shock.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench.
• Remove the upstream oxygen sensor (pre-cat) by using the O2 sensor socket.
• Inspect the sensor for damage and replace it if necessary.
• Install the new sensor and torque it to the manufacturer’s specifications (typically around 30 ft-lbs).
• Repeat the process for the downstream oxygen sensor (post-cat).

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, exhaust pipe cutter (if needed).
• Remove the exhaust heat shield if applicable by unscrewing the bolts.
• Disconnect the exhaust pipes connected to the catalytic converter, noting the orientation for reinstallation.
• Remove the catalytic converter from the vehicle.
• Inspect the new catalytic converter for any defects before installation.
• Install the new catalytic converter and connect the exhaust pipes, ensuring all bolts are tightened to the manufacturer's specifications (typically around 30-40 ft-lbs).
• Reinstall the heat shield if removed.

4. Clear Codes and Test

• Reconnect the negative battery terminal.
• Start the engine and allow it to reach operating temperature.
• Use the OBD-II scanner to clear the P0420 code from the vehicle's computer.
• Conduct a road test to verify proper operation, ensuring that the check engine light does not reappear.