how to fix the P0420 code on Honda Pilot Third Generation (2016-present)

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the vehicle battery to ensure safety.
• Allow the engine to cool completely before starting any repairs.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench.
• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors (usually near the exhaust manifold and after the catalytic converter).
  2. Use the O2 sensor socket to remove the upstream sensor first.
  3. Inspect the sensor for damage or contamination; replace it if necessary.
  4. Repeat the process for the downstream sensor.
  5. Torque the new sensors to the manufacturer's specifications (typically around 30 lb-ft).

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, jack stands, exhaust pipe cutter, gasket scraper.
• Sub-steps:
  1. Raise the vehicle using jack stands to access the exhaust system.
  2. Remove any mounting bolts securing the catalytic converter using the socket set.
  3. Cut the exhaust pipes if necessary to remove the old catalytic converter.
  4. Clean the exhaust flanges with a gasket scraper to ensure a good seal for the new converter.
  5. Install the new catalytic converter and tighten all bolts to the specified torque.
  6. Reconnect any oxygen sensors that were removed during this process.

4. Reset the Check Engine Light

• Tools Required: OBD-II scanner.
• Sub-steps:
  1. Reconnect the vehicle battery.
  2. Use the OBD-II scanner to clear the P0420 code from the vehicle's computer.
  3. Verify that all systems are functioning properly.