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

Solution

1. Preparation

• Gather required tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.

Tools Required:

• OBD-II scanner
• Multimeter
• Socket set
• Torque wrench
• Exhaust pipe cutter (if necessary)

2. Oxygen Sensor Inspection

• a. Locate the oxygen sensors: The upstream sensor is before the catalytic converter, and the downstream sensor is after it.
• b. Disconnect the electrical connectors from both oxygen sensors.
• c. Test the upstream sensor: Use the multimeter to check for a voltage reading between 0.1V to 0.9V while the engine is running. Replace if readings are outside this range.
• d. Test the downstream sensor: It should show a more stable voltage reading; replace if it fluctuates similarly to the upstream sensor.

3. Catalytic Converter Replacement

• a. Remove the exhaust system components: If the catalytic converter is damaged, use the socket set to unbolt the exhaust pipes at both ends of the catalytic converter.
• b. Cut the catalytic converter if necessary: Use an exhaust pipe cutter to remove it carefully.
• c. Install the new catalytic converter: Position the new converter and secure it with bolts. Make sure to follow the manufacturer's torque specifications for proper installation.
• d. Reconnect oxygen sensors: Attach the electrical connectors back to the respective sensors.

4. Clear Codes and Test

• a. Reconnect the negative battery terminal.
• b. Use the OBD-II scanner to clear the P0420 code.
• c. Start the engine and let it reach operating temperature.
• d. Take the vehicle for a test drive to ensure the P0420 code does not return.