my Honda Pilot YF4 (2023-Present) has a check engine light with code P0420, what to do?

Solution

1. Preparation

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

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench.
• Remove the pre-catalytic oxygen sensor:
  1. Locate the pre-catalytic O2 sensor (usually before the catalytic converter).
  2. Disconnect the electrical connector.
  3. Use the O2 sensor socket to unscrew the sensor.
• Inspect and replace the post-catalytic O2 sensor using the same method.

3. Inspect and Replace Catalytic Converter

• Tools Required: Socket set, jack and jack stands, torque wrench.
• Raise the vehicle securely with jack stands.
• Remove the exhaust components leading to the catalytic converter:
  1. Unbolt the flange at the exhaust manifold.
  2. Remove any hangers or brackets holding the exhaust pipe.
• Remove the old catalytic converter:
  1. Unscrew the bolts securing it to the exhaust pipe.
  2. Inspect the exhaust manifold for any debris.
• Install the new catalytic converter:
  1. Position the new converter and tighten the bolts to the manufacturer's torque specifications.
  2. Reattach any hangers or brackets removed previously.

4. Reconnect Battery and Clear Codes

• Reconnect the battery terminal.
• Use the OBD-II scanner to clear the error codes.
• Start the engine and check for leaks or unusual noises.