my Honda Civic 10th Generation (2016-2021) has a P0420 code what does that mean

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is on a level surface and engage the parking brake.

2. Inspect and Replace Oxygen Sensors (if necessary)

• Tools Required: O2 sensor socket, ratchet, torque wrench.
• Sub-steps:
  1. Disconnect the battery to ensure safety.
  2. Locate the upstream and downstream oxygen sensors (typically located before and after the catalytic converter).
  3. Use the O2 sensor socket to remove the sensors.
  4. Install the new sensors, ensuring they are torqued to manufacturer specifications (generally around 30 lb-ft).
  5. Reconnect the battery.

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, exhaust pipe cutter or saw.
• Sub-steps:
  1. Lift the vehicle using a jack and secure with jack stands.
  2. Remove the exhaust system components as necessary to access the catalytic converter.
  3. Cut or unbolt the catalytic converter from the exhaust system (be cautious of any hangers).
  4. Install the new catalytic converter, ensuring proper alignment and sealing.
  5. Torque all bolts to manufacturer specifications.
  6. Reinstall any components removed during the procedure.