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

Solution

1. Preparation

• Gather necessary tools and parts.
• Park the vehicle on a flat surface and engage the parking brake.
• Disconnect the battery to ensure safety while working on electrical components.

2. Inspect and Replace Oxygen Sensors (if faulty)

1. Locate the Oxygen Sensors: Identify the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
2. Remove the Sensors:
   • Use a specialized oxygen sensor socket to unscrew the sensors.
   • Disconnect the electrical connectors.
3. Install New Sensors:
   • Apply anti-seize compound on the threads of the new sensors.
   • Screw in the new sensors by hand, then tighten with the socket (typically 30 lb-ft torque).
   • Reconnect the electrical connectors.

3. Inspect and Replace Catalytic Converter (if necessary)

1. Remove the Exhaust Components:
   • Locate the catalytic converter and disconnect the exhaust pipe using a socket and ratchet.
   • Remove any mounting brackets or bolts securing the catalytic converter.
2. Inspect the Catalytic Converter:
   • Check for physical damage, cracks, or excessive clogging.
3. Install New Catalytic Converter:
   • Position the new catalytic converter in place.
   • Secure it using the original bolts and brackets, torqueing to manufacturer specifications (usually around 30 lb-ft).
   • Reconnect the exhaust pipe.

4. Clear Codes and Test Drive

1. Reconnect the Battery: Ensure the battery is connected.
2. Use the OBD-II Scanner: Clear the P0420 code from the computer.
3. Test Drive the Vehicle: Drive under various conditions to ensure the check engine light does not reappear.