how to fix P0420 code in my Honda Accord 10th Generation (2018-2022)

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is on a flat surface and the engine is cool.
• Disconnect the battery to prevent electrical issues.

2. Inspect and Replace Oxygen Sensors

1. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
2. Using an O2 sensor socket, remove the upstream oxygen sensor.
   • Tools Required: O2 sensor socket, ratchet, and extension.
3. Install the new upstream oxygen sensor, tightening it to the manufacturer's specifications (usually around 30 Nm).
4. Repeat the process for the downstream oxygen sensor if it is faulty or if the inspection indicates it is not functioning properly.

3. Inspect and Replace the Catalytic Converter

1. If the catalytic converter is damaged or clogged, it will need to be replaced.
2. Disconnect the exhaust pipe from the catalytic converter by removing the bolts or clamps.
   • Tools Required: Socket set, breaker bar.
3. Remove the mounting bolts securing the catalytic converter to the exhaust system.
4. Install the new catalytic converter, ensuring proper alignment and sealing.
5. Reattach the exhaust pipe and secure it with the bolts or clamps, tightening to the specified torque.

4. Clear Error Codes

1. Reconnect the battery.
2. Use the OBD-II scanner to clear the P0420 code from the vehicle's computer.
3. Start the engine and allow it to reach normal operating temperature.