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

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, socket set, torque wrench, safety glasses, gloves
• Clear any existing codes with the OBD-II scanner, and ensure the vehicle is parked on a level surface.

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors in the exhaust system.
  2. Disconnect the battery to ensure safety.
  3. Use the appropriate socket to unscrew the oxygen sensors from their locations.
  4. Inspect the sensors for damage or contamination.
  5. Install new oxygen sensors, tightening them to the manufacturer’s specified torque (usually around 30-40 lb-ft).
  6. Reconnect the battery.

3. Inspect and Replace the Catalytic Converter

• Sub-steps:
  1. Remove the heat shield if present by loosening the bolts with a socket set.
  2. Unscrew the catalytic converter from the exhaust pipes using the proper socket size.
  3. Inspect the catalytic converter for any physical damage, clogging, or excessive carbon buildup.
  4. Install the new catalytic converter, ensuring proper alignment and sealing.
  5. Tighten all bolts to the manufacturer’s specified torque (usually around 30-35 lb-ft).
  6. Reattach the heat shield if applicable.

4. Reset the Engine Control Module (ECM)

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