how do I fix P0420 code in 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 negative battery terminal to prevent electrical shorts.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench
• Inspect both upstream and downstream oxygen sensors for proper operation.
• If faulty, remove the old sensors:
  1. Disconnect the electrical connector.
  2. Use an O2 sensor socket to unscrew the sensor.
• Install the new sensor:
  1. Apply anti-seize compound to the threads.
  2. Hand-tighten the sensor, then torque to manufacturer specifications (usually around 30 lb-ft).
  3. Reconnect the electrical connector.

3. Inspect and Replace the Catalytic Converter

• Tools Required: Socket set, torque wrench, cutting torch (if necessary)
• If the catalytic converter is damaged or clogged, it must be replaced:
  1. Use a socket set to unbolt the catalytic converter from the exhaust system.
  2. If it's welded, carefully cut it out with a cutting torch.
  3. Position the new catalytic converter in place.
  4. Bolt it down according to the manufacturer’s torque specifications (typically around 50 lb-ft).
• Reconnect any exhaust hangers or brackets.

4. Clear the Error Code

• Reconnect the negative battery terminal.
• Use the OBD-II scanner to clear the P0420 code from the vehicle's computer.