how to fix P0420 code on Honda Accord 9th Generation (2013-2017)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to ensure safety.
• Raise the vehicle and secure it on jack stands.

2. Inspect and Replace Oxygen Sensors (if faulty)

• Tools Required: O2 sensor socket, wrench, dielectric grease.
• Remove the upstream (pre-catalytic) oxygen sensor using the O2 sensor socket.
• Inspect the sensor for damage or contamination. If it appears faulty, replace it with a new one.
• Repeat the process for the downstream (post-catalytic) oxygen sensor if necessary.
• Apply dielectric grease to the threads of the new sensors and install them, tightening them to the manufacturer's specifications (typically about 30 Nm or 22 lb-ft).

3. Check and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, exhaust gasket (if required).
• Disconnect the exhaust pipe from the catalytic converter by removing the bolts or clamps.
• Inspect the catalytic converter for any signs of damage or clogging.
• If replacement is needed, remove the old catalytic converter and install a new one, ensuring all gaskets are in place.
• Torque the bolts to the manufacturer's specifications (refer to service manual for exact values).

4. Clear Codes and Test Drive

• Reconnect the battery.
• Use the OBD-II scanner to clear the P0420 code.
• Start the vehicle and let it reach operating temperature.
• Take the vehicle for a test drive under various conditions to ensure proper functioning.