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

Solution

1. Preparation

• Gather the necessary tools and parts.
• Disconnect the battery to ensure safety while working on electrical systems.

2. Inspect and Replace Oxygen Sensors (if necessary)

• Tools Required: O2 sensor socket, ratchet, torque wrench.
• Sub-steps:
  1. Locate the upstream and downstream oxygen sensors (typically found before and after the catalytic converter).
  2. Use the O2 sensor socket to unscrew the oxygen sensors.
  3. Inspect the sensors; if they are corroded or damaged, replace them with new units.
  4. Apply anti-seize compound to the threads of the new sensors before installation.
  5. Torque the new sensors to the manufacturer’s specifications (usually around 30 lb-ft).

3. Catalytic Converter Inspection and Replacement

• Tools Required: Socket set, torque wrench, exhaust hanger removal tool.
• Sub-steps:
  1. Inspect the catalytic converter for any physical damage or signs of clogging.
  2. If replacement is needed, remove the exhaust hangers using the exhaust hanger removal tool.
  3. Unbolt the catalytic converter from the exhaust system using the socket set.
  4. Install the new catalytic converter in reverse order of removal.
  5. Torque the bolts to the manufacturer’s specifications.

4. Reconnect Battery and Clear Codes

• Sub-steps:
  1. Reconnect the battery terminals.
  2. Use the OBD-II scanner to clear the P0420 code from the vehicle's computer.