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

Solution

1. Preparation

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

2. Inspect and Replace Oxygen Sensors

• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors (usually found before and after the catalytic converter).
  2. Remove the electrical connector from the oxygen sensors.
  3. Use an oxygen sensor socket or wrench to unscrew the sensors from the exhaust system.
  4. Install the new oxygen sensors by screwing them into place and reconnecting the electrical connectors.
• Tools Required: Oxygen sensor socket, wrench, multimeter.

3. Inspect and Replace the Catalytic Converter

• Sub-steps:
  1. Remove any supporting brackets or heat shields that may obstruct access to the catalytic converter.
  2. Unbolt the catalytic converter from the exhaust pipes (use penetrating oil if bolts are rusted).
  3. Install the new catalytic converter, ensuring proper alignment and sealing.
  4. Torque the bolts to manufacturer specifications (consult repair manual for exact values).
• Tools Required: Socket set, torque wrench, penetrating oil.

4. Reconnect Battery and Clear Codes

• Reconnect the negative battery terminal.
• Use the OBD-II scanner to clear the P0420 code from the vehicle’s computer.