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

Solution

1. Preparation

• Ensure the vehicle is parked on a flat surface and the engine is cool.
• Disconnect the battery to prevent electrical shorts.
• Gather necessary tools and parts.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench.
• Remove the upstream (pre-cat) oxygen sensor:
  1. Use the O2 sensor socket to unscrew the sensor from the exhaust.
  2. Install the new O2 sensor and tighten to manufacturer's specifications (usually around 30-35 ft-lbs).
• Repeat for the downstream (post-cat) oxygen sensor if necessary.

3. Examine and Replace Catalytic Converter

• Tools Required: Socket set, jack stands, exhaust pipe cutter, gasket scraper.
• Raise the vehicle using jack stands and remove any heat shields if present.
• Disconnect the exhaust pipes connected to the catalytic converter using the socket set.
• Cut any clamps or bolts that may be holding the catalytic converter in place.
• Remove the old catalytic converter and clean the mating surfaces with a gasket scraper.
• Install the new catalytic converter:
  1. Position the new catalytic converter in place.
  2. Reconnect the exhaust pipes and secure them with bolts or clamps.
  3. Reinstall any heat shields if removed.

4. Reconnect Battery and Clear Codes

• Reconnect the battery terminals.
• Use an OBD-II scanner to clear the P0420 code from the ECU.
• Ensure that all connections are secure.