my Honda Civic 11th Generation (2022-Present) has a check engine light and P0420 code, what should I...

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, socket set, torque wrench, smoke machine.
• Disconnect the negative battery terminal to ensure safety.
• Allow the engine to cool before working on exhaust components.

2. Replace Faulty O2 Sensor

• Sub-steps:
  1. Locate the upstream O2 sensor (before the catalytic converter).
  2. Disconnect the electrical connector from the sensor.
  3. Use a wrench to unscrew the sensor from the exhaust manifold.
  4. Install the new O2 sensor by screwing it into place and tightening it to the manufacturer's torque specification (usually around 30 ft-lbs).
  5. Reconnect the electrical connector.

3. Replace Catalytic Converter (if necessary)

• Sub-steps:
  1. Unbolt the exhaust pipes connected to the catalytic converter using a socket set.
  2. Remove any heat shields or mounting brackets holding the catalytic converter.
  3. Install the new catalytic converter in the reverse order of removal, ensuring proper alignment.
  4. Torque all bolts to the manufacturer's specifications.

4. Clear Codes and Test

• Sub-steps:
  1. Reconnect the negative battery terminal.
  2. Use the OBD-II scanner to clear the P0420 code.
  3. Start the engine and let it reach operating temperature.
  4. Take the vehicle for a test drive to ensure the check engine light does not reappear.