how to fix P0420 code on 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 on a level surface and secure with jack stands if needed.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, wrench set
• Remove the upstream (pre-catalytic converter) oxygen sensor:
  1. Locate the sensor on the exhaust manifold.
  2. Use the O2 sensor socket to unscrew the sensor.
  3. Disconnect the wiring harness.
• Install the new upstream oxygen sensor:
  1. Apply anti-seize compound to the threads of the new sensor.
  2. Screw it into place by hand, then tighten to manufacturer specifications (typically around 30 ft-lbs).
  3. Connect the wiring harness.
• Repeat the process for the downstream (post-catalytic converter) oxygen sensor.

3. Inspect and Replace the Catalytic Converter

• Tools Required: Socket set, torque wrench, exhaust hanger removal tool
• Remove the old catalytic converter:
  1. Loosen the bolts connecting the catalytic converter to the exhaust pipe and the header.
  2. Remove any exhaust hangers using the exhaust hanger removal tool.
  3. Carefully take out the catalytic converter.
• Install the new catalytic converter:
  1. Position the new converter in place and attach it to the exhaust pipe and header.
  2. Tighten bolts to manufacturer specifications (usually around 25-30 ft-lbs).
  3. Reinstall any exhaust hangers.

4. Clear Codes and Test

• Reconnect the battery.
• Use the OBD-II scanner to clear the P0420 code from the vehicle's computer.
• Start the engine and let it idle for a few minutes, then take the vehicle for a test drive to verify the repair.