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

Solution

1. Preparation

• Gather tools and parts.
• Disconnect the negative battery terminal to ensure safety.
• Allow the vehicle to cool down before working on the exhaust system.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench.
• Sub-steps:
  1. Locate the upstream (pre-cat) and downstream (post-cat) oxygen sensors.
  2. Using the O2 sensor socket, carefully unscrew both sensors from their respective locations.
  3. Inspect the sensors for contamination or damage; replace if necessary.
  4. Install new sensors and torque to manufacturer specifications (usually around 30 lb-ft).

3. Inspect and Replace Catalytic Converter

• Tools Required: Socket set, torque wrench, penetrating oil, exhaust gasket.
• Sub-steps:
  1. Locate the catalytic converter in the exhaust system.
  2. Using penetrating oil, loosen and remove the bolts securing the catalytic converter.
  3. Inspect the converter for any signs of physical damage or blockage.
  4. If the catalytic converter is damaged, replace it with a new unit, ensuring to use the appropriate gasket.
  5. Torque the bolts to the manufacturer’s specified torque values (usually between 25-30 lb-ft).

4. Clear Codes and Test Drive

• Tools Required: OBD-II scanner.
• Sub-steps:
  1. Reconnect the negative battery terminal.
  2. Use the OBD-II scanner to clear the P0420 code.
  3. Perform a test drive to ensure that the check engine light does not reappear and to verify vehicle performance.