Honda Pilot YF4 (2023-Present) P0420 code, how to fix it?

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, multimeter, jack and jack stands, safety goggles, gloves.
• Disconnect the battery negative terminal to ensure safety before starting work.

2. Inspect and Fix Exhaust Leaks

• Sub-steps:
  1. Raise the vehicle using a jack and secure it on jack stands.
  2. Visually inspect the exhaust system from the engine to the tailpipe for any cracks or holes.
  3. Use an exhaust leak detector or soapy water to identify leaks.
  4. Repair or replace any damaged sections of the exhaust system using appropriate exhaust sealant or replacement parts.

3. Test and Replace Oxygen Sensors (if necessary)

• Sub-steps:
  1. Locate the upstream (pre-catalytic) and downstream (post-catalytic) oxygen sensors.
  2. Disconnect the electrical connectors from the sensors.
  3. Use a socket wrench to remove the sensors.
  4. Install new oxygen sensors by screwing them into place and reconnecting the electrical connectors.
  5. Ensure the sensors are installed to the manufacturer's torque specifications.

4. Replace Catalytic Converter (if necessary)

• Sub-steps:
  1. Remove the exhaust pipe connected to the catalytic converter using a socket set.
  2. Unbolt the catalytic converter from its mounting brackets.
  3. Install the new catalytic converter, ensuring it is properly aligned.
  4. Reattach the exhaust pipe and tighten all bolts to the specified torque value.
  5. Reconnect the battery terminal.