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

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the battery to prevent electrical shorts.

2. Inspect and Test Oxygen Sensors

• Tools Required: OBD-II scanner, multimeter
• Sub-steps:
  1. Reconnect the battery and start the engine.
  2. Use the OBD-II scanner to monitor the live data from the oxygen sensors.
  3. Compare the voltage outputs: the upstream sensor should fluctuate between 0.1V and 0.9V, while the downstream sensor should remain relatively stable.
  4. If the upstream sensor is faulty, replace it.

3. Check and Replace Catalytic Converter

• Tools Required: Socket set, torque wrench, penetrating oil, exhaust gasket
• Sub-steps:
  1. If the oxygen sensors are functioning correctly, inspect the catalytic converter for signs of damage or clogging.
  2. Remove any bolts securing the catalytic converter to the exhaust system using a socket set.
  3. Carefully detach the catalytic converter from the exhaust system; use penetrating oil if bolts are stuck.
  4. Replace with a new catalytic converter, ensuring to use a quality part compatible with the Honda CR-V 2017-2022.
  5. Torque the bolts to the manufacturer’s specifications.

4. Clear Codes and Test Drive

• Sub-steps:
  1. Reconnect the battery and use the OBD-II scanner to clear the P0420 code.
  2. Conduct a test drive to ensure the engine performs correctly and the check engine light does not reappear.