how to fix the P0420 code on my Honda CR-V Sixth Generation (2023-present)

Solution

1. Preparation

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

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, wrench set, torque wrench.
• Remove the upstream (pre-catalytic) oxygen sensor using the O2 sensor socket.
• Inspect the sensor for damage. If faulty, replace with a new sensor, torquing to manufacturer's specifications (typically around 30 ft-lbs).
• Repeat for the downstream (post-catalytic) oxygen sensor if it shows similar issues.

3. Inspect and Replace the Catalytic Converter

• Tools Required: Socket set, torque wrench, exhaust gasket, penetrating oil.
• Remove the bolts securing the catalytic converter to the exhaust manifold and the exhaust pipe. Use penetrating oil if bolts are rusted.
• Carefully detach the catalytic converter from the exhaust system.
• Inspect the exhaust gasket and replace if necessary.
• Install the new catalytic converter, ensuring it is aligned properly. Torque bolts to manufacturer specifications (usually around 30-40 ft-lbs).

4. Clear Codes and Test Drive

• Reconnect the battery and use the OBD-II scanner to clear the P0420 code.
• Perform a test drive of approximately 20-30 minutes to allow the vehicle to reach operating temperature and monitor for any reoccurrence of the check engine light.