how to fix P0420 code on my Honda CR-V Fifth Generation (2017-2022)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the battery to prevent electrical shorts.
• Ensure the vehicle is parked on a level surface and securely supported with jack stands.

2. Inspect and Replace Oxygen Sensors

• Tools Required: Oxygen sensor socket, ratchet, torque wrench.
• Remove the upstream oxygen sensor:
  • Use the oxygen sensor socket to unscrew the sensor from the exhaust manifold.
  • Inspect the sensor for damage or corrosion.
  • If faulty, replace with a new sensor, ensuring it is torqued to manufacturer specifications (typically around 30 ft-lbs).
• Remove the downstream oxygen sensor using the same method and replace if necessary.

3. Inspect and Replace the Catalytic Converter

• Tools Required: Socket set, torque wrench, cutting tool (if necessary for welded components).
• Remove the exhaust system components:
  • Disconnect any bolts or clamps securing the catalytic converter to the exhaust pipe.
  • If the catalytic converter is welded in place, carefully cut the welds with a cutting tool.
• Install the new catalytic converter:
  • Align the new converter with the exhaust system and secure it with bolts or clamps.
  • If welded, ensure proper welding technique is used to avoid leaks.
  • Torque bolts to manufacturer's specifications.

4. Clear Codes and Test Drive

• Reconnect the battery.
• Use the OBD-II scanner to clear any stored codes.
• Start the engine and perform a test drive to ensure the check engine light does not reappear.