my Honda Civic 11th Generation (2022-Present) has a check engine light and I'm getting a P0420 code

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, torque wrench, multimeter, exhaust pressure gauge, safety goggles, gloves.
• Ensure the vehicle is parked on a level surface, and the engine is cool before beginning repairs. Disconnect the negative battery terminal.

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors.
  2. Disconnect the electrical connectors from both sensors.
  3. Use the appropriate socket to remove the sensors from the exhaust pipe.
  4. Install the new oxygen sensors and torque to manufacturer specifications (typically around 30 lb-ft).
  5. Reconnect the electrical connectors.

3. Inspect and Replace the Catalytic Converter

• Sub-steps:
  1. Locate the catalytic converter in the exhaust system.
  2. Remove any heat shields or brackets securing the catalytic converter.
  3. Disconnect the exhaust pipes from both sides of the catalytic converter using a socket set.
  4. Inspect the catalytic converter for signs of damage or clogging.
  5. If necessary, replace the catalytic converter with a new unit, ensuring to use a part that meets OEM specifications.
  6. Reattach the exhaust pipes and torque bolts to manufacturer specifications (typically around 30 lb-ft).
  7. Reinstall heat shields or brackets if removed.

4. Reset the Check Engine Light

• Sub-steps:
  1. Reconnect the negative battery terminal.
  2. Use the OBD-II scanner to clear the P0420 code from the system.
  3. Start the engine and allow it to reach operating temperature.