how to fix P0420 code on Honda Accord 8th Generation (2008-2012)

Solution

1. Preparation

• Gather tools and parts needed.
• Disconnect the battery to ensure safety while working on the vehicle.

Tools Required:

• OBD-II scanner
• Multimeter
• Infrared thermometer
• Socket set
• Torque wrench

2. Inspect and Replace Oxygen Sensors

1. Locate the upstream and downstream oxygen sensors connected to the exhaust system.
2. Disconnect the electrical connectors from both sensors.
3. Use a socket wrench to unscrew the sensors from their mounting locations.
4. Install the new oxygen sensors, ensuring they are tightened to the manufacturer’s torque specifications (usually around 30 ft-lbs).
5. Reconnect the electrical connectors.

3. Inspect and Replace the Catalytic Converter

1. Remove any heat shields or brackets that may obstruct access to the catalytic converter.
2. Use a socket set to unbolt the catalytic converter from the exhaust manifold and the exhaust pipe.
3. Carefully remove the catalytic converter from the vehicle.
4. Install the new catalytic converter, ensuring a proper fit and alignment.
5. Tighten the bolts to the manufacturer's specifications (typically around 25 ft-lbs).
6. Reinstall any heat shields or brackets removed earlier.

4. Final Checks

1. Reconnect the battery.
2. Clear the P0420 code using the OBD-II scanner.
3. Start the engine and allow it to reach operating temperature.