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

Solution

1. Preparation

• Gather required tools and parts.
• Disconnect the negative battery terminal to ensure safety.
• Allow the vehicle to cool down before starting the work.

2. Inspect and Replace Oxygen Sensors (if necessary)

• Tools Required: O2 sensor socket, wrench set, torque wrench.
• Sub-steps:
  1. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
  2. Disconnect the electrical connectors from the sensors.
  3. Use the O2 sensor socket to remove the sensors from the exhaust manifold and catalytic converter.
  4. Install the new oxygen sensors and torque them to the manufacturer’s specifications (usually around 30 lb-ft).
  5. Reconnect the electrical connectors.

3. Replace Catalytic Converter (if necessary)

• Tools Required: Socket set, torque wrench, exhaust hanger removal tool, cutting tool (if necessary).
• Sub-steps:
  1. Remove the exhaust hangers using the exhaust hanger removal tool.
  2. Disconnect the catalytic converter from the exhaust system and the exhaust manifold.
  3. If the catalytic converter is welded in place, carefully cut it out using a cutting tool.
  4. Install the new catalytic converter, ensuring proper alignment with the exhaust system.
  5. Secure all connections using appropriate bolts and torque them to the manufacturer’s specifications.
  6. Reinstall exhaust hangers.

4. Reset the Check Engine Light

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