how to fix P0420 code on Honda Pilot YF3 (2016-2022)

Solution

1. Preparation

• Gather tools and parts needed.
• Disconnect the battery to prevent electrical shorts.
• Lift the vehicle using a jack and secure it with jack stands for access to the exhaust system.

2. Inspect and Replace O2 Sensors

• Tools Required: O2 sensor socket, torque wrench, multimeter.
• Remove the upstream O2 sensor:
  • Disconnect the electrical connector.
  • Use the O2 sensor socket to unscrew the sensor.
• Install the new upstream O2 sensor:
  • Apply anti-seize compound on the threads (if applicable).
  • Torque to manufacturer's specifications (typically around 30 lb-ft).
• Repeat the process for the downstream O2 sensor if it is faulty.

3. Examine and Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, exhaust sealant.
• Remove the catalytic converter:
  • Disconnect the exhaust pipes connected to the catalytic converter using the socket set.
  • Remove any mounting brackets or supports.
• Inspect the old catalytic converter for damage or blockage.
• Install the new catalytic converter:
  • Position the new unit and secure it with bolts.
  • Torque all bolts to the manufacturer's specifications (typically around 40 lb-ft).
• If applicable, use exhaust sealant to ensure a proper seal.

4. Reconnect Battery and Clear Codes

• Reconnect the vehicle’s battery.
• Use the OBD-II scanner to clear the P0420 code and any other codes that may have been stored.