how to fix P0420 code in Honda Pilot YF4 (2023-Present)

Solution

1. Preparation

• Gather all necessary tools and parts.
• Disconnect the vehicle's battery to prevent electrical shorts.
• Raise the vehicle securely on jack stands if undercarriage access is needed.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, wrench set, multimeter
• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors on the exhaust system.
  2. Use the O2 sensor socket to remove the upstream sensor carefully.
  3. Test the removed sensor using a multimeter to check for proper resistance and voltage output.
  4. If the sensor is faulty, replace it with a new one and reconnect it.
  5. Repeat the process for the downstream sensor if required.

3. Examine and Replace the Catalytic Converter

• Tools Required: Socket set, cutting tool (if necessary), torque wrench
• Sub-steps:
  1. If the catalytic converter shows signs of damage or clogging, it must be replaced.
  2. Remove the exhaust pipes connected to the catalytic converter by loosening the bolts.
  3. If necessary, cut the exhaust pipes to remove the old catalytic converter.
  4. Install the new catalytic converter, ensuring proper alignment with exhaust pipes.
  5. Torque all bolts to the manufacturer specifications stated in the service manual.

4. Clear Codes and Test Drive

• Tools Required: OBD-II scanner
• Sub-steps:
  1. Reconnect the vehicle's battery.
  2. Use the OBD-II scanner to clear the P0420 code from the vehicle's computer.
  3. Start the engine and allow it to reach operating temperature.
  4. Take the vehicle for a test drive to verify that the check engine light does not reappear.