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

Solution

1. Preparation

• Gather tools and replacement parts.
• Disconnect the battery to prevent electrical shorts.
• Allow the engine to cool if it has been running.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench.
• Remove the upstream (pre-catalytic) oxygen sensor:
  • Locate the sensor on the exhaust manifold.
  • Use the O2 sensor socket to unscrew the sensor.
  • Disconnect the electrical connector.
• Install the new upstream oxygen sensor:
  • Connect the electrical connector and screw it in place.
  • Torque to manufacturer's specification (typically around 30 lb-ft).
• Repeat the process for the downstream (post-catalytic) oxygen sensor if necessary.

3. Examine and Replace Catalytic Converter

• Tools Required: Socket set, torque wrench, exhaust pipe cutter/welder (if needed).
• Remove the exhaust pipe connected to the catalytic converter:
  • Loosen and remove the bolts connecting the pipe to the converter.
  • Cut the pipe if it is welded.
• Remove the catalytic converter:
  • Unbolt the catalytic converter from the exhaust manifold and exhaust pipe.
• Install the new catalytic converter:
  • Position the new converter and bolt it in place, ensuring proper alignment.
  • Torque to manufacturer's specifications (consult service manual).
• Reconnect the exhaust pipe securely.

4. Reset the Engine Control Module (ECM)

• Tools Required: OBD-II scanner.
• Reconnect the battery.
• Use the OBD-II scanner to clear the P0420 code from the ECM.