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

Solution

1. Preparation

• Gather tools and parts needed.
• Disconnect the battery to avoid any electrical shorts.
• Raise the vehicle using jack stands for access to the exhaust system.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, wrench set.
• Remove the upstream and downstream oxygen sensors using the O2 sensor socket.
• Inspect the sensors for carbon buildup or damage.
• If faulty, replace with new OEM or quality aftermarket sensors.
• Reinstall the sensors and ensure they are tightened to manufacturer's specifications.

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, exhaust hanger removal tool.
• Remove the exhaust pipes connected to the catalytic converter by loosening the bolts.
• Carefully detach the catalytic converter, noting the orientation for reinstallation.
• Inspect the converter for signs of clogging or damage (e.g., dents, holes).
• If damaged, replace with a new catalytic converter that meets OEM specifications.
• Reinstall the catalytic converter and exhaust pipes, tightening bolts to the specified torque.

4. Clear the Codes

• Reconnect the battery.
• Use the OBD-II scanner to clear the P0420 code and reset the system.