what does code P0420 mean for Honda Civic 11th Generation (2022-Present)

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Replace Faulty Oxygen Sensors

1. Locate the upstream and downstream oxygen sensors.
2. Use an O2 sensor socket to remove the faulty sensor(s).
3. Apply anti-seize compound to the threads of the new oxygen sensor.
4. Install the new oxygen sensor and torque to manufacturer specifications (typically around 33 ft-lbs).
5. Reconnect the wiring harness.

3. Inspect and Replace the Catalytic Converter

1. Remove the exhaust heat shield if necessary (may require a socket set).
2. Detach the exhaust pipes connected to the catalytic converter using a wrench or socket.
3. Remove any mounting brackets or bolts securing the catalytic converter.
4. Replace the old catalytic converter with a new unit, ensuring proper alignment.
5. Reattach all exhaust pipes and brackets, torquing them to specifications.
6. Reinstall the exhaust heat shield if removed.

4. Reset the Engine Control Module (ECM)

1. Reconnect the negative battery terminal.
2. Use an OBD-II scanner to clear the P0420 code from the ECM.
3. Start the engine and let it idle for a few minutes.