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

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 prevent any electrical issues.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench.
• Remove the pre-catalytic oxygen sensor from the exhaust manifold using the O2 sensor socket.
• Inspect the sensor for damage or contamination.
• If faulty, replace with a new sensor, tightening to manufacturer specifications (typically around 30 Nm).
• Repeat for the post-catalytic oxygen sensor if necessary.

3. Examine and Replace Catalytic Converter

• Tools Required: Socket set, torque wrench, exhaust pipe cutter (if necessary).
• Locate the catalytic converter under the vehicle and inspect for damage or clogging.
• If replacement is needed, disconnect the exhaust pipes using a socket set, ensuring to remove all mounting bolts.
• Carefully remove the old catalytic converter and install the new one, ensuring proper alignment.
• Torque all bolts to manufacturer specifications (usually around 40-50 Nm).

4. Clear Error Codes

• Reconnect the battery.
• Use an OBD-II scanner to clear the P0420 code and perform a test drive to check for reoccurrence.