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

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, socket set, torque wrench, safety goggles, gloves.
• Ensure the vehicle is parked on a flat surface and the engine is cool.

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  1. Disconnect the battery to ensure safety.
  2. Locate the upstream (pre-catalytic) oxygen sensor and the downstream (post-catalytic) oxygen sensor.
  3. Unplug the connectors from both sensors.
  4. Use a socket wrench to remove the sensors from the exhaust manifold and catalytic converter.
  5. Install new oxygen sensors, ensuring they are tightened to the manufacturer’s torque specifications (usually around 30-40 lb-ft).
  6. Reconnect the battery.

3. Inspect and Replace the Catalytic Converter

• Sub-steps:
  1. Raise the vehicle using a jack and secure it with jack stands.
  2. Locate the catalytic converter in the exhaust system.
  3. Inspect for any physical damage such as dents or cracks.
  4. If damaged, remove the catalytic converter bolts using the socket set and take out the component.
  5. Install a new catalytic converter, ensuring it is properly aligned.
  6. Tighten the bolts to the manufacturer's torque specifications (typically around 25-30 lb-ft).
  7. Lower the vehicle.

4. Clear Codes and Test Drive

• Sub-steps:
  1. Use the OBD-II scanner to clear the P0420 code.
  2. Start the vehicle and allow it to reach operating temperature.
  3. Perform a test drive to ensure the check engine light does not reappear.