how to fix P0420 code on my Honda Pilot YF4 (2023-Present)

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a flat surface and the engine is cool.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench.
• Sub-steps:
  1. Disconnect the negative battery terminal to ensure safety.
  2. Locate the upstream and downstream oxygen sensors (usually near the exhaust manifold and after the catalytic converter).
  3. Use the O2 sensor socket to remove the sensors.
  4. Install new oxygen sensors and torque them to the manufacturer’s specifications (typically around 30 lb-ft).
  5. Reconnect the negative battery terminal.

3. Inspect and Replace Catalytic Converter (if necessary)

• Tools Required: Jack and jack stands or lift, socket set, torque wrench.
• Sub-steps:
  1. Raise the vehicle safely using a jack and secure with jack stands.
  2. Remove the exhaust pipes connected to the catalytic converter by loosening the bolts.
  3. Unbolt the catalytic converter from the exhaust manifold and remove it from the vehicle.
  4. Install the new catalytic converter, ensuring proper alignment.
  5. Torque the bolts to manufacturer specifications to avoid leaks.
  6. Reconnect exhaust pipes and check for secure fitting.