what does error code P0420 mean for my Honda Pilot YF3 (2016-2022)

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Disconnect the battery to prevent electrical shorts.
• Raise the vehicle on jack stands for easier access to the exhaust system.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, wrench set, multimeter.
• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors in the exhaust system.
  2. Disconnect the electrical connectors from both sensors.
  3. Remove the sensors using the O2 sensor socket.
  4. Inspect the threads and connectors for damage, and replace if necessary.
  5. Install new oxygen sensors in reverse order, ensuring proper torque (typically 30 lb-ft).
  6. Reconnect the electrical connectors.

3. Inspect and Replace Catalytic Converter

• Tools Required: Socket set, torque wrench, exhaust gasket.
• Sub-steps:
  1. Identify the catalytic converter location in the exhaust system.
  2. Disconnect the exhaust pipes from the catalytic converter by removing the bolts and nuts.
  3. Remove any mounting brackets holding the catalytic converter in place.
  4. Remove the catalytic converter from the exhaust system.
  5. Install the new catalytic converter, ensuring all gaskets are replaced and properly sealed.
  6. Torque all bolts to the manufacturer’s specifications (check service manual for exact values).

4. Reset the Engine Control Module (ECM)

• Tools Required: OBD-II scanner.
• Sub-steps:
  1. Reconnect the vehicle's battery.
  2. Use the OBD-II scanner to clear the P0420 error code from the ECM.
  3. Perform a test drive to allow the ECM to relearn and monitor sensor readings.