how to fix P0420 code on Honda Civic 11th Generation (2022-Present)

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Ensure the vehicle is on a flat surface and secure it with wheel chocks.
• Disconnect the battery to prevent electrical issues during repair.

2. Inspect and Replace Oxygen Sensors

1. Locate the Oxygen Sensors:

   • Identify the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.

2. Remove the Oxygen Sensors:

   • Use an oxygen sensor socket and ratchet to unscrew the sensors from their mounts.
   • Disconnect the electrical connectors by releasing the clips.

3. Install New Oxygen Sensors:

   • Apply anti-seize compound to the threads of the new sensors.
   • Install the new sensors by threading them into place and tightening them to the manufacturer’s specified torque (usually around 30 Nm).
   • Reconnect the electrical connectors.

3. Inspect and Replace Catalytic Converter (if necessary)

1. Inspect the Catalytic Converter:

   • Check for physical damage or signs of clogging.
   • If testing indicates inefficiency, proceed to replacement.

2. Remove the Catalytic Converter:

   • Disconnect the exhaust pipe from the catalytic converter using a socket set.
   • Remove any heat shields and mounting bolts securing the catalytic converter.

3. Install New Catalytic Converter:

   • Position the new catalytic converter in place, ensuring proper alignment with exhaust pipes.
   • Tighten bolts to the manufacturer’s specified torque.
   • Reinstall heat shields if applicable.

4. Clear Error Codes

• Reconnect the vehicle's battery.
• Use an OBD-II scanner to clear the P0420 code from the system.