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

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, torque wrench, multimeter, back pressure gauge, safety goggles, gloves.
• Disconnect the battery to prevent electrical shock.
• Allow the engine to cool before working on the exhaust system.

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors.
  2. Disconnect the electrical connectors from both sensors.
  3. Use an O2 sensor socket to unscrew and remove the faulty sensor(s).
  4. Install the new oxygen sensor(s) by threading them in and tightening them to the manufacturer's specifications (typically 30 Nm or 22 lb-ft).
  5. Reconnect the electrical connectors.

3. Inspect and Replace Catalytic Converter

• Sub-steps:
  1. Locate the catalytic converter in the exhaust system.
  2. Remove the exhaust bolts securing the catalytic converter using a socket set.
  3. Carefully detach the catalytic converter from the exhaust system.
  4. Inspect the gasket and replace if damaged.
  5. Install the new catalytic converter by aligning it with the exhaust pipes and securing it with bolts.
  6. Torque the bolts to the manufacturer's specifications (typically 30 Nm or 22 lb-ft).

4. Reset the OBD-II System

• Sub-steps:
  1. Reconnect the battery.
  2. Use an OBD-II scanner to clear the P0420 code from the vehicle's computer.
  3. Start the engine and allow it to reach normal operating temperature.