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

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a flat surface, and the engine is off.
• Disconnect the battery to prevent any electrical shorts.

2. Replace Oxygen Sensors (if faulty)

• Remove the upstream oxygen sensor using an O2 sensor socket.
• Install the new upstream oxygen sensor and torque to manufacturer specifications (typically around 30 lb-ft).
• Repeat the process for the downstream oxygen sensor if it was found to be faulty.
• Reconnect the battery.

3. Inspect or Replace Catalytic Converter

• Lift the vehicle securely on jack stands.
• Disconnect the exhaust pipes from the catalytic converter using a socket set.
• Remove the catalytic converter from the vehicle by unbolting it from the mounting points.
• Inspect the catalytic converter for damage; if it's clogged or damaged, replace it with a new one.
• Install the new catalytic converter and tighten bolts to manufacturer specifications.

4. Clear Error Codes

• Use an OBD-II scanner to clear the P0420 code from the vehicle's computer.
• Start the engine and allow it to reach operating temperature.