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 engage the parking brake.
• Disconnect the battery to avoid electrical shorts.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench.

• For the upstream O2 sensor:

  1. Locate the upstream oxygen sensor (before the catalytic converter).
  2. Using the O2 sensor socket, remove the sensor carefully.
  3. Install the new oxygen sensor and torque it to the manufacturer's specification (typically around 30 lb-ft).

• For the downstream O2 sensor:

  1. Locate the downstream oxygen sensor (after the catalytic converter).
  2. Remove the sensor using the O2 sensor socket.
  3. Install the new downstream O2 sensor and torque it as specified.

3. Inspect and Replace the Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, gasket scraper.
• 1. Raise the vehicle safely on jack stands.
• 1. Remove the exhaust pipe bolts connecting the catalytic converter to the exhaust system using a socket.
• 1. Remove any hangers or brackets securing the catalytic converter.
• 1. Inspect the catalytic converter visually for damage or clogging, and replace it if necessary.
• 1. Install the new catalytic converter, ensuring all gaskets are in place.
• 1. Torque all bolts to the manufacturer’s specifications.

4. Reconnect Battery and Clear Codes

• 1. Reconnect the battery terminals.
• 1. Use the OBD-II scanner to clear the P0420 code from the ECM.
• 1. Start the engine and let it idle for a few minutes to ensure proper operation.